EOC REVIEW QUESTIONS
Biology
1. An abiotic factor affecting the behavior
and survival of such organisms as robins
and violets is the
A.
population of rabbits
B.
length of daylight
C.
presence of harmful bacteria
D.
number of herbivores
2. Which group in the food web represented in the
diagram would most likely have the greatest
biomass?
A.
corn and oats
B.
hawks and owls
C.
mice and rats
D.
snakes and raccoons
3. The diagram shows nutritional relationships
between organisms of various populations in a
food web. Which organisms are classified as
secondary consumers?
A.
hawk, grasshopper, and mouse
B.
rabbit, mouse, and snake
C.
grasshopper, frog, and rabbit
D.
snake, hawk, and frog
4. The diagram represents a food web. If this food
web is represented as a pyramid of biomass, the
level of the pyramid with the least amount of
biomass would contain the
A.
grasshopper
B.
grass
C.
mouse
D.
hawk
5. Which is an abiotic factor that functions as a
limiting factor for the autotrophs in the
ecosystem represented in the diagram?
A.
grasshopper
B.
light
C.
fish
D.
hawk
6. An biotic factor affecting the behavior and
survival of such organisms as robins and
violets is the
A.
wind speed
B.
length of daylight
C.
presence of water
D.
number of herbivores
7. For many decades, certain areas of New York
State have remained as hardwood forests
containing predominantly oak and hickory
trees. These forested areas will most likely
A.
B.
C.
D.
remain indefinitely and not be
affected by environmental influences.
reach maturity and change in the near
future.
be destroyed by environmental
changes and never return to their
present forms.
continue in their present forms unless
affected by environmental factors.
8. What are the abiotic factors represented in
this illustration of an aquarium?
A.
snail, gravel, and water
B.
snail, fish, and plants
C.
water, light, and gravel
D.
plants, light and water
9. Which event illustrates the interaction of
an abiotic factor with a biotic factor in the
environment?
A.
The lamprey eel survives by
parasitizing trout.
B.
The temperature of water affects
its oxygen level.
C.
The low light intensity of the
forest affects the growth of pine
trees.
D.
A gypsy moth caterpillar eats the
leaves of an apple tree.
10. Which nutritional term best describes the
following statement? Fish living deep in
the ocean obtain energy by eating animal
remains that sink to the bottom from
upper water regions.
A.
B.
C.
D.
Scavenging
Mutualism
Parasitism
Saprophytism
11. The graph provides information about the population of
deer in a given area between 1900 and 1945. Which
statement identifies the most likely reason that the
carrying capacity of the area to support deer decreased
between 1925 and 1930?
A.
The deer population decreased in 1926.
B.
The number of predators increased between
1915 and 1925.
C.
The deer population became too large.
D.
An unusually cold winter occurred in 1918.
12. If two different bird species in the
same habitat require the same type
of nesting site, both species will
most likely
A. interbreed and share their
nesting sites
B. compete for the nesting sites
C. change their nesting site
requirements
D. use the nests of other bird
species
13. Select the term most closely
associated with the statement:
Certain fungi use dead organic
matter for food.
A. mutualism
B. commensalism
C. parasitism
D. saprophytism
14. The chart shows the environmental functions that some
organisms perform in a stable ecosystem. How would a
decrease in the number of organisms that perform these
functions most likely affect the ecosystem?
A.
The interactions between other organisms would
stop immediately.
B.
The functions carried out by these organisms
would no longer be necessary.
C.
The ecosystem would remain stable.
D.
The ecosystem would become less stable.
15.
The diagram shows the relationships between
organisms in and around a pond. One additional biotic
factor needed to make this a stable ecosystem is the
presence of
A.
producers
B.
herbivores
C.
decomposers
D.
consumers
16. Young rabbits that eat grass are sometimes
eaten by raccoons, which also eat seeds
and berries. Bacteria help to decompose the
excretions of the raccoon. Which statement
about these nutritional relationships is
accurate?
A. Bacteria are scavengers.
B. Rabbits are secondary consumers.
C. Raccoons eat only producers.
D. Raccoons are both primary and
secondary consumers.
17.
In the diagram of the nitrogen cycle, letters A through
E represent organisms carrying on a process at that
particular point in the cycle. Letter B represents
A.
scavengers
B.
decomposers
C.
autotrophs
D.
carnivores
18. What is the major environmental
factor limiting the numbers of
autotrophs at great depths in
the ocean?
A. type of seafloor
B. amount of light
C. availability of minerals
D. absence of biotic factors
19.
Which statement best describes some organisms in
the food web shown in the diagram?
A.
Minnows and fish are primary consumers.
B.
Algae and floating plants are decomposers.
C.
Aquatic crustaceans are omnivores.
D.
Raccoons, fish, and ducks are secondary
consumers.
20.
The letters in the diagram represent the processes
involved in the water cycle. Which letter represents the
process of transpiration?
A.
A
B.
B
C.
C
D.
D
21. Which term best describes the mosquito
larvae?
A. producer
B. parasite
C. carnivore
D. consumer
22. The nitrogen cycle is most directly
dependent upon the
A. process of transpiration in
autotrophs
B. ability of consumers to move from
place to place
C. metabolic activities of soil bacteria
D. evaporation of water from the
Earth's surface
23.
An ecosystem is represented in the diagram. This
ecosystem will be self-sustaining if
A.
the organisms labeled A outnumber the
organisms labeled B
B.
the organisms labeled A are equal in
number to the organisms labeled B
C.
the type of organisms represented by B are
eliminated
D.
materials cycle between the organisms
labeled A and the organisms labeled B
24. In a pure culture, Paramecium
caudatum grew and flourished. In a
mixed culture with P. aurelia, all P.
caudatum died within 16 days, while
the P. aurelia survived. This
observation illustrates
A. saprophytism
B. gradualism
C. competition
D. evolution
25. In an ecosystem, the more living
requirements that two different
species have in common, the more
intense will be their
A. ecological succession
B. competition
C. energy requirements
D. evolution
26. Organisms that obtain and ingest organic
molecules for their nutrition are
classified as
A. autotrophs
B. producers
C. algae
D. heterotrophs
27. Select the term most closely
associated with the statement: The
roots of the mistletoe plant absorb
nutrients from living oak trees,
causing some damage to the tissues
of the trees.
A. mutualism
B. commensalism
C. parasitism
D. saprophytism
E. competition
28. Which change would usually increase
competition among the squirrel population
in a certain area?
A.
an epidemic of rabies among
squirrels
B.
an increase in the number of
squirrels killed on the highways
C.
an increase in the number of hawks
that prey on squirrels
D.
a temporary increase in the squirrel
reproduction rate
29. The diagram shows a marine biome. Autotrophs
in zones A through C depend on the metabolic
activities of other organisms for a continuing
supply of
A.
water
B.
carbohydrates
C.
respiratory enzymes
D.
carbon dioxide
30.
The table shows the type of food consumed by
various animals in a community. Under normal
conditions, which organisms in this community
would have the greatest amount of stored energy?
A.
grasshoppers
B.
snakes
C.
plants
D.
hawks
31. Graphs of the data from
laboratory investigations are
used to
A. observe general trends in the
data
B. make the observed data
more accurate
C. prevent errors in measuring
data
D. help change the original data
tables
32. A new drug for the treatment of asthma is
tested on 100 people. The people are
evenly divided into two groups. One
group is given the drug, and the other
group is given a glucose pill. The group
that is given the glucose pill serves as
the
A. experimental group
B. limiting factor
C. control
D. indicator
33.
The diagram shows nutritional relationships
between organisms of various populations in a
food web. Based on their ecological role,
hawks and snakes may be classified as
A.
predators
B.
parasites
C.
autotrophs
D.
decomposers
34. A student set up a terrarium containing
moist soil, several plants, and snails. The
terrarium was placed in a sunny area.
Which factor is not essential for the
maintenance of the terrarium?
A. a constant source of energy
B. a living system capable of
incorporating energy into organic
compounds
C. a cycling of materials between
organisms and their environment
D. the introduction of another
heterotroph into the terrarium
35. Nitrogen-fixing bacteria live on the roots
of leguminous plants in swellings called
nodules. The bacteria synthesize
nitrogen compounds that are used by the
plants, and the plants provide moisture
and nutrients for the bacteria. The
interaction between the nitrogen-fixing
bacteria and the leguminous plants is
known as
A. parasitism
B. mutualism
C. saprophytism
D. commensalism
36. Which gas is excreted as a waste
product of autotrophic nutrition in
maple trees?
A. nitrogen
B. oxygen
C. carbon dioxide
D. methane
37. Which factor is not considered by
ecologists when they evaluate the
impact of human activities on an
ecosystem?
A. amount of energy released from
the Sun
B. quality of the atmosphere
C. degree of biodiversity
D. location of power plants
38. A new type of fuel gives off an excessive
amount of smoke. Before this type of
fuel is widely used, an ecologist would
most likely want to know
A. what effect the smoke will have
on the environment
B. how much it will cost to produce
the fuel
C. how long it will take to produce the
fuel
D. if the fuel will be widely accepted by
consumers
39.
The graph shows data on the average life expectancy
of humans. The change in life expectancy from 1910 to
1970 is most likely the result of
A.
an increase in poor land-use management that
affected the quality of the topsoil
B.
the introduction of technology that had a
negative impact on air quality
C.
a decrease in natural checks, such as disease,
on the population
D.
a widespread increase in the presence of lead
and other heavy metals in water supplies
40. Which human activity is most
responsible for the other three
human activities?
A. increasing demand for food
B. increasing loss of farmland
C. increasing human population
D. increasing air pollution
41.
The chart describes four classes of compounds.
Which class of compounds includes the compound
represented in the diagram below?
1. A
2. B
3. C
4. D
42. Which chemical formula represents a
carbohydrate?
A. CH4
B. C3H7O2N
C. C12H22O11
D. CO2
43. A simple sugar such as glucose is
classified as a
A. monosaccharide
B. polysaccharide
C. disaccharide
D. nucleotide
44. In a lipid synthesis reaction, the
greatest number of fatty acid
molecules that could combine with
one glycerol molecule is
A. 1
B. 2
C. 3
D. 6
45.
Base your answer on the diagram of the
chemical equation which represents a
metabolic activity and your knowledge of
biology. Molecule C belongs in the general
class of substances known as
A.
vitamins
B.
minerals
C.
inorganic acids
D.
organic compounds
46. Plants store carbohydrates in the
form of
A. amino acids
B. fatty acids
C. starch
D. nucleic acids
47. An element found in all proteins but
not found in carbohydrates and
lipids is
A. carbon
B. hydrogen
C. oxygen
D. nitrogen
48. Maltase is an enzyme that is not able
to catalyze the synthesis of lipids
because maltase
A. has a specific active site
B. is a small molecule
C. cannot attach to ribosomes
D. is a simple sugar
49. Which characteristic allows enzymes to
function in a specific way?
A.
Enzymes are complex
compounds composed of
starch.
B.
Each enzyme has a
characteristic shape.
C.
Enzymes are long, complex fats.
D.
Each enzyme is made up of four
subunits.
50. Lipase, maltase, and protease are
members of a group of catalysts
known as
A. enzymes
B. hormones
C. carbohydrates
D. fats
51. A block of wood is measured, as shown
in the diagram. What is the length of the
wooden block in millimeters?
A. 2.60 mm
B. 26.0 mm
C. 260 mm
D. 2,600 mm
52. A sample of food containing one type of
a large molecule was treated with a
specific digestive enzyme. Nutrient
tests performed on the resulting
products showed the presence of simple
sugars, only. Based on these test
results, the original large molecules
contained in the sample were molecules
of
A. protein
B. glucose
C. starch
D. DNA
53. What usually results when an organism
fails to maintain homeostasis?
A. Growth rates within organs become
equal.
B. The organism becomes ill or may
die.
C. A constant sugar supply for the cells
is produced.
D. The water balance in the tissues of
the organism stabilizes.
54. Every single-celled organism is able to
survive because it carries out
A. metabolic activities
B. autotrophic nutrition
C. heterotrophic nutrition
D. sexual reproduction
55.
The diagram shows the structural formulas of
six molecules. Which two molecules are used
in the synthesis of a lipid?
A.
A and D
B.
B and E
C.
B and F
D.
D and E
56.
The results of an experiment to determine
the composition of the cytoplasm of
organism X are summarized in the data
table. What percentage of the cytoplasm is
composed of organic material?
A. 15
B. 20
C. 22
D. 92
57. Base your answer on the chemical
equation shown in the diagram and your
knowledge of biology. A dipeptide is
represented by
A. A
B. B
C. C
D. D
58. Small molecules are combined to
form large molecules by the life
function of
A. regulation
B. excretion
C. transport
D. synthesis
59. Which factor contributed most to the
development of the cell theory?
A. the discovery of many new species
during the last century
B. the development of advanced
techniques to determine the
chemical composition of
substances
C. the increase in knowledge
concerning factors influencing the
rate of evolution
D. the improvement in microscopes
and microscopic techniques during
the last two centuries
60. An iodine test of a tomato plant leaf revealed that
starch was present at 5:00 p.m. on a sunny
afternoon in July. When a similar leaf from the
same tomato plant was tested with iodine at 6:00
a.m. the next morning, the test indicated that
less starch was present in this leaf than in the
leaf tested the day before. This reduction in
starch content occurred because starch was
A.
changed into cellulose
B.
transported out of the leaves through the
stomates
C.
conducted downward toward the roots
through vessels
D.
digested into simple sugars
61. Which diagram represents an organelle
that contains the enzymes needed to
synthesize ATP in the presence of
oxygen?
A. 1
B. 2
C. 3
D. 4
62. The transfer of energy from
nutrients to ATP is accomplished
most directly by the process of
A. cyclosis
B. diffusion
C. cellular respiration
D. glucose synthesis
63. In a bean plant, which reaction will
release the greatest amount of
energy?
A. aerobic respiration of a glucose
molecule.
B. anaerobic respiration of a
glucose molecule.
C. synthesis of a chlorophyll
molecule.
D. hydrolysis of a cellulose
molecule.

64. Which process is represented by the
arrow in the diagram?
A. growth
B. respiration
C. regulation
D. excretion
65. Which term includes all the activities
required to keep an organism alive?
A. growth
B. excretion
C. metabolism
D. nutrition
66.
A solution of an enzyme normally found in the
human body was added to a flask containing a
solution of proteins in distilled water, and then the
flask was stoppered. This mixture was then
maintained at a temperature of 27°C and a pH of 7
for 48 hours. When the mixture was analyzed, the
presence of amino acids was noted. Which substance
would most likely be present in the solution in the
flask after 48 hours?
A.
amino acids, only
B.
amino acids and polypeptides, only
C.
polypeptides, amino acids, and enzyme
molecules
D.
polysaccharides, amino acids, and enzyme
molecules
67. The diagram shows the structural formula of a
molecule. Which statement best describes this
molecule?
A. It has the ability to control heredity.
B. It has the ability to control reactions.
C. It has a high energy content.
D. It is involved in photosynthesis.
68. A simple sugar such as glucose is
classified as a
A. monosaccharide
B. polysaccharide
C. disaccharide
D. nucleotide
69. In which process are simple materials
chemically combined to form more
complex materials?
A. synthesis
B. pinocytosis
C. hydrolysis
D. cyclosis
70.Humans breathe more rapidly during
exercise than before it because during
exercise the blood contains
A.
an increased level of oxygen
B.
a decreased number of red blood
cells
C.
an increased level of carbon dioxide
D.
a decreased amount of hemoglobin
71. Microscopic examination of an animal cell
reveals the presence of plasma membrane but
no cell wall. Which additional structures
would normally be present within this cell?
A. starch grains
B. centrioles
C. chloroplasts
D. large vacuoles
72. Which statement best describes the plasma
membrane of a living plant cell?
A. It selectively regulates the passage of
substances into and out of the cell.
B. It is composed of proteins and
carbohydrates only.
C. It has the same permeability to all
substances found inside or outside the
cell.
D. It is a double protein layer with floating
lipid molecules.
73.
The graph shows the relative rates of action of
four enzymes, A, B, C, and D. A solution with a
pH of 6 contains enzyme C and its substrate. If a
base is gradually added to this solution, the rate
of action of enzyme C would most likely
A. remain constant
B. increase, then decrease
C. decrease, then increase
D. decrease constantly
74. The diagram illustrates a biochemical process
that occurs in organisms. The substance
labeled "catalyst" is also known as
A. a hormone
B. an enzyme
C. an antibody
D. an inorganic compound
75. A student has a hamburger, french fries,
and soda for lunch. Which sequence
represents the correct order of events in
the nutritional processing of this food?
A.
B.
C.
D.
ingestion -> digestion -> absorption > egestion
digestion -> absorption -> ingestion > egestion
digestion -> egestion -> ingestion > absorption
ingestion -> absorption -> digestion > egestion
76. Which section is not part of the cell
theory?
A. Cells are the structural units in
living things.
B. Cells are the functional units in
living things.
C. New cells arise from preexisting
cells.
D. New cells have nuclei identical to
those of preexisting cells.
77. Which substances are inorganic
compounds?
A. water and salts
B. proteins and carbohydrates
C. fats and oils
D. enzymes and hormones
78.Compound X increases the rate of the
reaction below.
Compound X is most likely
A. an enzyme
B. a lipid molecule
C. an indicator
D. an ADP molecule
79. Organisms that obtain and ingest
organic molecules for their nutrition
are classified as
A. autotrophs
B. producers
C. algae
D. heterotrophs
80. Which statement best describes extracellular
digestion?
A. Large insoluble molecules are converted
to small soluble molecules outside the
cell.
B. Large insoluble molecules are converted
to small soluble molecules within the cell.
C. Small soluble molecules are converted to
large insoluble molecules outside the cell.
D. Small soluble molecules are converted to
large insoluble molecules within the cell.
81. Amino acid molecules are bonded
together in a specific sequence on cell
structures known as
A. ribosomes
B. vacuoles
C. mitochondria
D. centromeres
82. A student sees the image to the left when observing the
letter "f" with the low-power objective lens of a
microscope. Which diagram below most closely
resembles the image the student will see after
switching to high power?
A.
B.
C.
D.
1
2
3
4
83.
The diagram represents the field of view of a compound
light microscope. Three unicellular organisms are
located across the diameter of the field. What is the
approximate length of each unicellular organism?
A.
250 μm
B.
500 μm
C.
1,000 μm
D.
1,500 μm
84. A block of wood is measured, as shown
in the diagram. What is the length of the
wooden block in millimeters?
A. 2.60 mm
B. 26.0 mm
C. 260 mm
D. 2,600 mm
85. Iodine and Benedict's solution were both
used to test for certain nutrients in a
sample of food. If both tests were
positive for the nutrients, the sample
must contain
A. polysaccharide and simple sugar
B. protein and fat
B. carbohydrate and lipid
D. polysaccharide and protein
86. In plants glucose is converted to
cellulose, and in human muscle cells,
glucose is converted to glycogen. These
processes are examples of which life
activity?
A. regulation
B. respiration
C. synthesis
D. excretion
87. Which organelles outside the cell nucleus
contain genetic material?
A. lysosomes and cell walls
B. chloroplasts and mitochondria
C. endoplasmic reticula and cell
membranes
D. vacuoles and Golgi complex
88. Which technique enabled scientists
in the 1800's to identify cell
organelles?
A. electron microscopy
B. ultracentrifugation
C. staining
D. dissection
89. Which chemical formula represents a
carbohydrate?
A. CH4
B. C3H7O2N
C. C12H22O11
D. CO2
The equation below summarizes the process
that produces the flashing light of a firefly.
90. The molecule luciferin is broken down, and
energy is released in the form of heat and light.
In this process, luciferase functions as
A.
a reactant
B.
a substrate
C.
an inorganic catalyst
D.
an enzyme
91. Which phrase best describes cellular
respiration, a process that occurs
continuously in the cells of organisms?
A. removal of oxygen from the cells of an
organism.
B. conversion of light energy into the
chemical bond energy of organic
molecules.
C. transport of materials within cells and
throughout the bodies of multicellular
organisms.
D. changing of stored chemical energy in
food molecules to a form usable by
organisms.
92. Which statement best describes one of the events
taking place in the chemical reaction below?
A.
B.
C.
D.
Energy is being stored as a result of aerobic
respiration.
Fermentation is taking place, resulting in
the synthesis of ATP.
Energy is being released for metabolic
activities.
Photosynthesis is taking place, resulting in
the storage of energy.
93. What is a direct result of aerobic
respiration?
A. The potential energy of glucose is
transferred to ATP molecules.
B. The enzymes for anaerobic
respiration are produced and stored
in lysosomes.
C. Lactic acid is produced in muscle
tissue.
D. Alcohol is produced by yeast and
bacteria.
94. The energy an organism requires to
transport materials and eliminate wastes
is obtained directly from
A. DNA
B. starch
C. hormones
D. ATP
95. Which structure of the woody plant
represented the organ of photosynthesis?
A. A
C. C
B.
B
D.
D
96.Which process produces the greatest
quantity of ATP per molecule of glucose
oxidized?
A.
aerobic respiration
B.
lactic acid production
C.
photosynthesis
D.
fermentation
97. Which process requires cellular energy?
A. diffusion
B. passive transport
C. active transport
D. osmosis
98. Which activity is illustrated in the diagram of
an ameba?
A. egestion
B. synthesis
C. respiration
D. ingestion
99. The life function of transport in an
organism directly involves those
activities used to
A. absorb and distribute materials.
B. obtain and hydrolyze materials.
C. release energy from food .
D. produce cellular waste products.
100. Which enzyme regulates the reaction
represented by the word equation:
lipid + water = fatty acids + glycerol
A. amylase
B. lipase
C. ATPase
D. protease
101. Oxygen serves as a hydrogen acceptor
during aerobic respiration. This results
in the production of
A. glucose
B. lactic acid
C. glycerol
D. water
102. Which condition is necessary for an
experiment to yield useful data?
A. Similar results should be obtained
when the experiment is repeated
B. Only the expected results should be
considered each time the
experiment is performed.
C. The hypothesis must be correct.
D. The experimental period must be
short.
103. A new concept that is tested in a
scientific investigation is known as
A. a theory
B. the hypothesis
C. in inference
D. an observation
104. Which term best describes the interaction between
the physical and living factors shown in the
diagram?
A.
a biosphere
B.
an ecosystem
C.
a community
D.
a biome
105. What is the basic unit of structure and
function in protists and monerans?
A. cell
B. tissue
C. organ
D. system
106. Plants store carbohydrates in the
form of
A. amino acids
B. fatty acids
C. starch
D. nucleic acids
107.An element found in all proteins but
not found in carbohydrates and
lipids is
A. carbon
B. hydrogen
C. oxygen
D. nitrogen
108.Maltase is an enzyme that is not able
to catalyze the synthesis of lipids
because maltase
A. has a specific active site
B. is a small molecule
C. cannot attach to ribosomes
D. is a simple sugar
109. Which characteristic allows enzymes to
function in a specific way?
A. Enzymes are complex
compounds composed of
starch.
B. Each enzyme has a
characteristic shape.
C. Enzymes are long, complex fats.
D. Each enzyme is made up of four
subunits.
110. Lipase, maltase, and protease are
members of a group of catalysts
known as
A. enzymes
B. hormones
C. carbohydrates
D. fats
111. Base your answer on the reactions shown in the
graphic. The X in each reaction represents various
A.
energy sources
B.
final products
C.
reactants
D.
enzymes
112. If the chemical reaction shown in the diagram
takes place in an organism that requires
sunlight to produce substance X , the
organism must be
A. a heterotroph
B. an annelid
C. an autotroph
D. a fungus
113. The transfer of energy from nutrients to
ATP is accomplished most directly by
the process of
A. cyclosis
B. diffusion
C. cellular respiration
D. glucose synthesis
114. The products of aerobic respiration in
green plants are ATP and
A. lactic acid and oxygen
B. glucose and oxygen
C. carbon dioxide and water
D. carbon dioxide and ethyl alcohol
115. What is the basic unit of structure and
function in arachnids and insects?
A. cell
B. tissue
C. organ
D. system
116. Which diagram represents an organelle that is
the “packaging center” of the cell?
A. 1
B. 2
C. 3
D. 4
117. Which scientists developed the double
helix model of the DNA molecule?
A. Watson and Crick
B. Hardy and Weinberg
C. Darwin and Lamarck
D. Weismann and Miller
118. Amino acid molecules are bonded
together in a specific sequence on cell
structures known as
A. ribosomes
B. vacuoles
C. mitochondria
D. centromeres
119. In addition to a phosphate group, a
DNA nucleotide could contain
A. thymine and deoxyribose
B. uracil and deoxyribose
C. thymine and ribose
D. uracil and ribose
120.In addition to a phosphate group, a
RNA nucleotide could contain
A. thymine and deoxyribose
B. uracil and deoxyribose
C. thymine and ribose
D. uracil and ribose
121. Fermentation is anaerobic respiration.
The fermentation of yeast normally
yields
A. lactic acid, CO2, and 2 ATP
B. alcohol, CO2, and 36 ATP
C. alcohol, CO2, and 2 ATP
D. CO2, H2O, and 36 ATP
122. In a grasshopper, the movement of
glucose from the digestive tract to
muscle cells is most directly a result of
A. ingestion and digestion
B. absorption and circulation
C. anaerobic respiration
D. protein synthesis
123.Which gas is excreted as a waste
product of autotrophic nutrition in
maple trees?
A. nitrogen
B. oxygen
C. carbon dioxide
D. methane
124. In the setup shown in the diagram, which
color light will cause the plant to produce the
smallest number of gas bubbles?
A. red
B. orange
C. blue
D. green
125. Base your answer on the diagram which
represents some of the events that take place
in a chloroplast and on your knowledge of
biology. Gas E would most likely represent
A. CO2
B. N2
C. O2
D. H2O
126. All the black-footed ferrets inhabiting a
given forest constitute a
A. population
B. community
C. biome
D. biosphere
127. The graph illustrates the growth curves for two
types of bacteria (A and B) under differing pH
values. Bacteria A grows best in a medium that is
A.
slightly acid
B.
neutral
C.
slightly basic
D.
very basic
128.Which substance is an organic
compound?
A. water
B. table salt
C. Ammonia
D. insulin
129.Which organelles are present in
plant cells only?
A. lysosomes and mitochondria
B. chloroplasts and cell walls
C. endoplasmic reticula and cell
membranes
D. vacuoles and Golgi Apparatus
130. An insect’s exoskeleton is made of a
carbohydrate known as
A. glycogen
B. chitin
C. cellulose
D. glycerol
131.Amino acid molecules are bonded
together in a specific sequence on
cell structures known as
A. ribosomes
B. vacuoles
C. mitochondria
D. centromeres
132. Which organelles outside the cell nucleus
contain digestive enzymes?
A. lysosomes
B. chloroplasts
C. endoplasmic reticula
D. Golgi Apparatus
133. In an ecosystem, the more living
requirements that two different species
have in common, the more intense will
be their
A. ecological succession
B. competition
C. energy requirements
D. evolution
134. Which statement best describes an energy
pyramid?
A. There is more energy at the consumer
level than at the producer level.
B. There is more energy at the producer
level that at the consumer level.
C. There is more energy at the secondaryconsumer level than at the primaryconsumer level.
D. There is more energy at the decomposer
level than at the consumer level.
135.In a plant, which structure enables
photosynthesis to take place?
A. stem
B. pollen tube
C. stamen
D. leaf
136. Which cell organelle can best be
compared to cleanup crew for the cell?
A. Ribosomes
B. Mitochondria
C. Endoplasmic Reticulum
D. Lysosomes
137. The main components of the plasma
membrane are:
A. Proteins
B. Cytokines
C. Phosphates
D. Phospholipids
138. A student is observing a cell using a
microscope. Which of the following
observations about the cell indicates that
it must be part of a plant cell?
A. its well-defined nucleus
B. its water filled vacuole
C. its boxlike structure
D. its cell membrane
139. Cells are like miniature factories. Inside
the cell are small structures which carry
out the various functions of the cell.
These structures inside the cell are
known as _________________.
A. Organs
B. Organelles
C. Protoplasm
D. Intracells
140. Which sequence of terms is in the correct
order from simplest to most complex?
A. cells-tissues-organs-organ systems
B. tissues-organisms-cells-organ systems
C. cells-tissues-organ systems-organs
D. organs-organisms-organ system-cells
141. A cell is placed in a beaker containing a
hypertonic solution. What happens to
the cell?
A. the cell gains water
B. the cell shrinks
C. the cell gains water
D. the cell is lysed
142. In the lungs, the movement of carbon
dioxide out of the cells and oxygen into
cells can best be explained by which of
the following processes?
A. active transport
B. diffusion
C. endocytosis
D. osmosis
143. While cleaning a saltwater aquarium,
students placed the aquarium plants in a
container of distilled water. What effects
will this leave on the plants?
A. the plant cells will swell
B. the plant cells will shrink
C. the plant cells will separate
D. the plant cells will remain the same
144. Which of these describes the function of
the cell membrane?
A. Maintaining homeostasis
B. Cell division
C. Producing energy
D. Protein synthesis
145. An enzyme-substrate complex may
result from the interaction of molecules
of:
A. glucose and lipase
B. proteins and protease
C. fats and amylase
D. sucrose and maltase
146.Which process is illustrated in the
diagram?
A. crossing-over
B. nondisjunction
C. sex determination
D. independent assortment
147. Which diagram represents a pair of
homologous chromosomes?
A.
B.
C.
D.
1
2
3
4
148.Some basic principles of heredity were
established when Gregor Mendel
crossed large numbers of pea plants
and then
A. mapped the loci of various genes
B. analyzed the mathematical ratios
of certain traits in the offspring
C. microdissected the chromosomes
of the offspring
D. determined how many genes had
mutated
149. The diagram represents a pair of
homologous chromosomes. Which allelic
combination represents the heterozygous
condition for a trait?
A.
B.
C.
D.
Aa
BB
aa
aB
150.Random separation and
distribution of homologous
chromosomes occurs during
A. cleavage
B. mitotic cell division
C. fertilization
D. meiotic cell division
151.
The basic principles of
genetics were established in
the 19th century by
A. Francis Crick
B. Charles Darwin
C. Jean Lamarck
D. Gregor Mendel
152. In the diagram of two homologous
chromosomes, what do R and r
represent?
A. two different alleles
B. two gametes that can form a
zygote
C. two identical alleles
D. two chromosomes in a hybrid pea
plant
153.Random separation and
distribution of homologous
chromosomes occurs during
A. cleavage
B. mitotic cell division
C. fertilization
D. meiotic cell division
154.Gregor Mendel developed some basic
principles of heredity based on his
A. dissection of the flowers of both
tall and short African violet plants
B. microscopic observation of the
nuclei of fruit fly cells
C. biochemical analysis of DNA
produced in the F2 generations of
roan cattle
D. mathematical analysis of the
offspring produced by crossing
pea plants
155.In minks, the gene for brown fur (B) is
dominant over the gene for silver fur
(b). Which set of genotypes represents
a cross that could produce offspring
with silver fur from parents that both
have brown fur?
A. Bb ×Bb
B.
C.
D.
BB ×bb
BB ×Bb
Bb × bb
156.Heterozygous
A.
B.
C.
D.
Means
___________.
Information about heritable traits.
Unique/different molecular forms
of a gene that are possible at a
given locus.
Crossing over results.
Having a pair of identical alleles at
a gene.
157. Phenotype is _______________.
A. Observable (expressed, can
physically see) heritable traits.
B. Unique/different molecular forms
of a gene that are possible at a
given locus.
C. Genetic recombination results.
D. Particular genes carried by an
individual.
158.
A.
B.
C.
D.
A recessive allele
_____________.
is represented by a capital
letter, such as “A”.
is represented by a lower
case letter, such as “a”.
has the ability to mask other
traits.
both a and c.
159.Hybrid offspring
A. Is when offspring of genetic
crosses inherit a pair of identical
alleles for a trait.
B. Is when offspring of genetic
crosses inherit a pair of nonidentical alleles for a trait.
C. Does not represent a pure bred
organism.
D. Both A & C
E. Both B & C
160.Males have ___________.
A. One X sex chromosome and one Y
sex chromosome.
B. Two Y sex chromosomes.
C. Two X sex chromosomes.
D. Only one sex chromosome which
would be X.
E. Only one sex chromosome which
would be Y.
161.In poultry, feathered shank (F) is
dominant over clean shank ( f ). If the
hen's genotype is represented by ff and
the rooster's genotype is Ff, what
percentage of their offspring would be
expected to have feathered shanks?
A. 0%
B. 50%
C. 75%
D. 100%
162.If the pattern of inheritance for a trait
is complete dominance, then an
organism heterozygous for the trait
would normally express
A.
the recessive trait, only
B.
the dominant trait, only
C.
a blend of the recessive and
dominate traits
D.
a phenotype unlike that of either
parent
3. In certain rats, black fur is
dominant over white fur. If two
rats, both heterozygous for fur
color, are mated, their offspring
would be expected to have
A. four different genotypes and two
different colors
B. two different genotypes and three
different colors
C. three different genotypes and two
different colors
D. three different genotypes and three
different colors
4. Base your answer on the diagram and your
knowledge of biology. Which process results
in the formation of chromatid Z from
chromatids A and B?
A.
intermediate inheritance
B.
nondisjunction
C.
codominance
D.
crossing-over
5. The principles of dominance,
segregation, and independent
assortment resulted from studies by
Mendel of the inheritance of traits in
A.
four-o'clock flowers
B.
roan cattle
C.
fruit flies
D.
pea plants
Day 43
Starter
1. The core of a virus may contain
either DNA or RNA. To identify
which nucleic acid is present, a
biochemist could chemically analyze
the virus for the presence of
A.
guanine
B.
ribose
C.
cytosine
D.
phosphate
2.
In watermelon plants, the allele for
solid green fruit (G) is dominant over
the allele for striped fruit (g). Pollen
from a flower of a homozygous green
watermelon plant is used to pollinate a
flower from a heterozygous green
watermelon plant. What percent of the
offspring of this cross will bear striped
watermelons?
A. 0%
B. 25%
C. 50%
D. 100%
3. The diagram represents human gametes. Which
statement best describes the fertilized egg that
would result if this sperm cell and egg cell unite?
A.
It would contain 44 chromosomes and
develop into a male.
B.
It would contain 44 chromosomes and
develop into a female.
C.
It would contain 46 sex chromosomes
and develop into a female.
D.
It would contain 46 sex chromosomes
and develop into a male.
4. In humans, normal color vision (N) is
dominant over color blindness (n). A
man and woman with normal color
vision produced two colorblind sons and
two daughters with normal vision.
Choose from the diagram the correct
parental genotypes.
A.
XNY and XNXN
B.
XNY and XNXn
C.
XnY and XNXN
D.
XnY and XnXn
5. There are three alleles for the ABO blood group
in humans. Why are there only two alleles
normally present in any individual?
A.
The alleles for the ABO blood group
always segregate independently during
meiosis.
B.
Each parent contributes only one allele
for the ABO blood group to the offspring.
C.
Every gene for the ABO blood group must
be recessive.
D.
The alleles that determine the ABO blood
group are on the X-chromosome.
Day 44
Starter
1. After gametogenesis takes place,
which process restores the diploid
chromosome number of the species
for the next generation?
A.
oogenesis
B.
mitosis
C.
fertilization
D.
meiosis
2. In humans, which cell is produced
most directly by mitotic cell
division?
A.
a sperm cell
B.
a skin cell
C.
an egg cell
D.
a zygote
3.
Which diagram below represents an
organism that uses external
fertilization for the production of
offspring?
1.1
A.
B.
C.
D.
1
2
3
4
4. Asexual reproduction of diploid
organisms normally results in new
organisms that contain cells with
A.
more chromosomes than are
found in the cells of the parent
B.
the n number of chromosomes
C.
the 2n number of
chromosomes
D.
fewer chromosomes that are
found in the cells of the parent
5. Each body cell of a chimpanzee
contains 48 chromosomes. How
many chromosomes would normally
be present in a gamete produced by
this chimpanzee?
A.
24
B.
36
C.
48
D.
96
Day 45
Starter
1. Which diagram below represents binary
fission?
A.
B.
C.
D.
1
2
3
4
2. Which process is represented by the
series of diagrams?
A.
gametogenesis
B.
fertilization
C.
mitotic cell division
D.
meiotic cell division
3.
The diagram represents some stages in
the development of an embryo. Which
stage represents a zygote?
A.
B.
C.
D.
A
B
C
D
4.
Warts result when certain viruses
cause skin cells to reproduce at a
high rate. This rapid reproduction
of skin cells is due to the viruses
stimulating
A. cellular digestion
B. mitotic cell division
C. synthesis processes
D. meiotic cell division
5.
Which statement is true regarding
plants produced by vegetative
propagation?
A. They normally exhibit only
dominant characteristics.
B. They normally have the
monoploid number of
chromosomes.
C. They normally obtain most of
their nourishment from the seed.
D. They are normally genetically
identical to the parent.
Day 46
Starter
1.
In many aquatic vertebrates,
reproduction involves external
fertilization. What is a characteristic of
this type of fertilization?
A. Gametes fuse outside the body of
the female.
B. Gametes fuse in the moist
reproductive tract of the female.
C. Offspring produced have twice as
many chromosomes as each of the
parents.
D. Offspring produced have only half
the number of chromosomes as
each of the parents.
2.
Which is a true statement about the process
illustrated in the diagram?
A.
It is the beginning of embryonic
development and occurs only in a
freshwater environment.
B.
It is the beginning of regeneration and
occurs only within the female.
C.
It is the beginning of embryonic
development and occurs within the
female or in water.
D.
It is the beginning of ovule formation
and occurs on the stigma of flowers.
3.
The diagram shows a sequence of
events. The sequence of events from
rabbits to zygote is known as
A. sexual reproduction
B. fission
C. sporulation
D. vegetative propagation
4.
Most cells in the body of a fruit fly
contain eight chromosomes. How
many of these chromosomes were
contributed by each parent of the
fruit fly?
A. 8
B. 2
C. 16
D. 4
5.
Base your answer on the diagram of
some stages in the development of an
embryo and on your knowledge of biology.
Diagram D illustrates a
A.
late blastula stage
B.
gastrula
C.
fetus
D.
stage of meiosis
Day 47
Starter
1.
Which is a true statement about
people with the genotype IAIB for
blood type?
A. They have two alleles that are
codominant.
B. They exhibit a type O
phenotype.
C. They are homozygous for
blood type A.
D. They can have only type O
children.
2. The diagrams represent paired double stranded
chromosomes that contain genes indicated by
letters. When does the process illustrated by
the diagrams occur?
A. in meiosis, after disjunction of homologous
chromosomes
B. in mitosis, after replication of chromosomes
C. in meiosis, during crossing-over of
homologous chromosomes
D. in mitosis, while chromosomes are attaching
to spindle fibers
3. In chickens, rose comb (R) is dominant
over single comb (r). When a
heterozygous rose-combed rooster is
mated with several single-combed hens,
what is the expected phenotypic ratio of
the offspring?
A.
100% rose-combed
B.
100% single-combed
C.
75% rose-combed and 25%
single-combed
D.
50% rose-combed and 50%
single-combed
4.
A man with normal color vision
married a woman with normal
color vision whose father was
colorblind. Their chance of having
a colorblind daughter is
A. 0%
B. 25%
C. 75%
D. 100%
5.
Genes for two different traits that
are located next to each other on
the same chromosome would most
likely be
A. inherited separately
B. codominant
C. recombined
D. inherited together
Day 48
Starter
1.
The process of cleavage leads
most directly to the formation of a
A. zygote
B. gonad
C. gamete
D. blastula
2.
Normal mitotic cell division results in
each daughter cell having
A. half the number of chromosomes
as the parent cell.
B. the same number and kinds of
chromosomes as the parent cell
C. the same number but different
kinds of chromosomes as the
parent cell
D. twice the number of chromosomes
as the parent cell
3.
Which reproductive adaptation is
characteristic of most fish and
amphibians?
A. Their gametes always fuse in
the moist reproductive tract of
the female.
B. They only produce nonmetals
gametes.
C. They produce small numbers
of eggs.
D.
Their zygotes are formed in the
external environment.

4.
In the diagrams of mitotic cell division,
which structure is present in diagram B
but not in diagram A?
A. centriole
B. cell plate
C. cell membrane
D. cytoplasm
5. In animals, which condition is
necessary for external
fertilization?
A.
the presence of carbon dioxide
B.
a moist environment
C.
a motile egg cell
D.
the absence of light
Day 49
Starter
1.Base your answer on the diagram which
represents a biochemical process that occurs in
a cell and your knowledge of biology. The
organelle labeled Z represents a
A. ribosome
B. golgi body
C. mitochondrion
D. nucleus
2.
In many placental mammals,
reproduction involves internal
fertilization. What is a characteristic of
this type of fertilization?
A. Gametes fuse outside the body of
the female.
B. Gametes fuse in the moist
reproductive tract of the female.
C. Offspring produced have twice as
many chromosomes as each of the
parents.
D. Offspring produced have only half
the number of chromosomes as
each of the parents.
3.
Two genes for two different traits
located on the same chromosome
are said to be
A. homozygous
B. independently assorted
C. mutagenic agents
D. linked
4.
The principles of dominance,
segregation, and independent
assortment resulted from studies
by Mendel of the inheritance of
traits in
A. four-o'clock flowers
B. roan cattle
C. fruit flies
D. pea plants
5.
A colorblind man married a woman
with normal color vision whose mother
was colorblind. Their chance of having
a normal vision daughter is
A. 0%
B. 25%
C. 75%
D. 100%
Day 50
Starter
1. In cats, a pair of X-chromosomes will produce
a female, while an X- and a Y-chromosome
will produce a male. Fur color is controlled by
a single pair of alleles. The alleles for orange
fur and for black fur are located on the Xchromosome, only. Tortoiseshell cats have one
allele for orange fur and one for black fur.
Which statement concerning fur color in cats
is true?
A.
Only female cats can be tortoiseshell.
B.
Only male cats can be tortoiseshell.
C.
Males need two alleles to have orange
fur.
D.
Males need two alleles to have black
fur.
2.
A diploid cell of a normal human
male contains
A. 22 autosomes and two Ychromosomes
B. 22 pairs of autosomes and two
Y-chromosomes
C. 22 pairs of autosomes, one Xchromosome, and one Ychromosome
D. 22 autosomes and two Xchromosomes
3.
The diagram represents stages in the
development of a chordate. Which
process is represented in diagram 4?
A. fertilization
B. gametogenesis
C. mitosis
D. meiosis
4.
In animals that reproduce sexually,
which is the correct sequence for the
development of a new organism?
A. gametes - zygote - fertilization embryo
B. fertilization - zygote - gametes embryo
C. zygote - gametes - fertilization embryo
D. gametes - fertilization - zygote embryo
5.
A cell with a diploid chromosome
number of 12 divided two times,
producing four cells with six
chromosomes each. The process that
produced these four cells was most
likely
A. internal fertilization
B. external fertilization
C. mitotic cell division
D. meiotic cell division
Day 51
Starter
1.
Potatoes, strawberries, and
seedless oranges are generally
produced by an asexual means of
reproduction known as
A. sporulation
B. budding
C. binary fission
D. vegetative propagation
2.
Complex organisms produce sex
cells that unite during fertilization,
forming a single cell known as
A. an embryo
B. a gamete
C. a gonad
D. a zygote
3.
Which statement best explains the
significance of meiosis in the evolution
of a species?
A. Meiosis produces eggs and sperm
that are alike.
B. Meiosis provides for chromosomal
variation in the gametes produced
by an organism.
C. Equal numbers of eggs and sperm
are produced by meiosis.
D. The gametes produced by meiosis
ensure the continuation of any
particular species by asexual
reproduction.
4.
The production of motile
monoploid gametes takes place in
A. ureters
B. ovaries
C. male gonads
D. gastric glands
5.
During meiotic cell division, the
process in which homologous pairs
of chromosomes separate and
move apart is known as
A. internal fertilization
B. regeneration
C. binary fission
D. disjunction
Day 52
Starter
1. Which organism is most likely to
use anaerobic respiration?
A.
bird
B.
moss
C.
tree
D.
yeast
2. What process produces many
variations in phenotypes?
A. Independent assortment
B. Asexual reproduction
C. Regeneration
D.Cloning
3. A plant species lives in an area with
limited sunlight. Which physical
adaptation would be most useful to
the plant?
A.
colorful flowers
B.
large leaves
C.
deep roots
D.
thin cuticle
4. RNA and DNA are which type of
organic compound?
A.
carbohydrate
B.
lipid
C.
nucleic acid
D.
protein
5. What advantage do sexually
reproducing organisms have over
asexually reproducing organisms?
A.
genetic variation
B.
genetic stability
C.
increased fertilization rate
D.
increased reproductive rate
Day 37
Starter
1.
In humans, which cell is produced
most directly by mitotic cell
division?
A. a sperm cell
B. a skin cell
C. an egg cell
D. a zygote
2. The individual strands of a doublestranded chromosome are joined
together by a
A.
cilium
B.
cyton
C.
chromatid
D.
centromere
3.
The diagrams represent a cell
process. If the cell in Diagram 1
contains 4 chromosomes, what is the
total number of chromosomes in each
cell in Diagram 3?
A. 8
B. 2
C. 16
D. 4
4.
Which process is represented by the
series of diagrams?
A. gametogenesis
B. fertilization
C. mitotic cell division
D. meiotic cell division
5.
Warts result when certain viruses
cause skin cells to reproduce at a
high rate. This rapid reproduction
of skin cells is due to the viruses
stimulating
A. cellular digestion
B. mitotic cell division
C. synthesis processes
D. meiotic cell division
EOC Review
Open Ended
Questions
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Plants store carbohydrates as what?
The two top receiving chambers of the heart.
Enzymes found in the mouth that digest
sugar?
Why is water considered inorganic?
“ose” at the end of a word denotes a what?
The organ that produces insulin.
Proteins that speed up chemical reactions in
the body?
Animal-like protists are called what?
Plant-like protists are called what?
Name the two types of fungus-like protists.
“ase” at the end of a word denotes a what?
Whip-like structure in some unicellular
organisms used for mobility.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
Developed the double helix model of DNA.
What is the exoskeleton of an arthropod
composed of?
The most posterior segment of an arthropod.
Two cell organelles outside the nucleus that
has its own DNA.
First man to pen the term “cell.”
Number of chromosomes in a normal human.
Pairs of chromosomes having genes for
different traits.
Sleep-like state of animals in extreme heat as
in a desert.
Where segmented worms store food before
its ground in their body.
In humans, which cells are produced by
meiotic cell division?
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
This cell organelle is the site of
photosynthesis.
Movement of a substance from high to low
concentration.
The movement of a substance from low to
high concentration requiring energy
The energy molecule in the body.
The diffusion of water.
The Father of Genetics.
This organ mixes food with hydrochloric acid
and gastric juices making it a soup mixture.
Tube that carries food from the mouth to the
stomach.
Learned behavior by constant practice.
Exchange of information between organisms.
Instinctive seasonal movement of animals
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
An inherited behavior in animals.
Learned behavior by trying something to see
if
it works to get what the animal wants.
½ the number of chromosomes.
Pumping chambers of the heart.
A change in the amino acid sequence of DNA.
Name the four types of blood in humans.
Gregor Mendel did his work on what
organisms?
Where absorption takes place in digestive
system?
Helps digestion by storing bile.
A mutation may be passed on to future
generations if it occurs within what
specialized cells?
45. Invertebrates does not possess what?
46. Innate behavior by which animals form a
social ranking within a group.
47. Vestigial organ found attached to the large
intestines in humans.
48. A learned behavior that occurs by using
past experience to respond to a new situation.
49. What is the chemical formula for glucose?
50. The level with the greatest biomass in an
energy pyramid.
51. An animal that feeds exclusively on
herbivores.
52. Another name for a dependent variable.
53. Another name for an independent variable.
54. Amino acids are held together by what kind
of bond?
56. An organism that is able to make its own
food.
57. An organism that is not able to make its
own food.
58. What is the simple sugar found in RNA?
59. The part of an experiment that is not
changed and is used for comparison.
60. Part of the digestive system in segmented
worms where absorption occurs.
61. Hair-like projections that line the
underside of many unicellular organisms.
62. Invented the first microscope.
63. State of reduced metabolism occurring
when animals sleep during the winter.
64. Structures located underneath an earth
worm used for mobility.
66. Food grinding organ in a segmented worm.
67. What kind of circulatory system does the
segmented worm have?
68. These vessels carry blood away from the
heart.
69. The vein where oxygenated blood occurs.
70. Artery where deoxygenated blood occur.
71. Gland where steroids and adrenalin is made.
72. Gland that produces estrogen in females.
73. Gland that produces testosterone in males.
74. The master gland that controls the other
glands in the endocrine system.
75. The large bone found in birds that provides
strength for flight.
76. The egg laying mammals are known as what?
77. Kangaroos are what type of mammals?
79.
80.
81.
82.
83.
84.
85.
86.
An organism that eats only producers.
An organism that feed exclusively on other
consumers.
Organisms that feed on dead or decaying
animals.
Organisms that feed on plants and animals
(consumers and producers).
A word that means “living together.’
A symbiotic relationship where both benefit.
A symbiotic relationship where one benefit
and the other is neither helped nor harmed.
A symbiotic relationship where one benefit at
the expense of the other.