A scientist conducted an experiment to test the hypothesis that maple seeds exposed to acid rain will take longer to germinate than seeds exposed to normal rain, which has a pH of 5.6. The scientist set up four groups, each containing 200 maple seeds. The water used for each group had a different pH value: 5.6, 4.0, 3.0, and 2.0. All other conditions were kept the same. After ten days, the number of seeds that had germinated in each group was counted. I. -Identify the control group in this experiment. II. -Identify the dependent and independent variable in this experiment. III. -State one example of experimental results that would indicate that acid rain, which has a pH between 4.5 and 4.0, could be responsible for a decrease in the number of young maple trees in some forest regions. A student states that exercise will affect the number of times a person can squeeze a clothespin in a certain amount of time. An experiment is carried out to test this hypothesis. One group of ten students sits quietly before squeezing a clothespin as many times as possible during a one-minute interval. A second group of ten students does 25 jumping jacks before squeezing a clothespin as many times a possible during a one-minute interval. State one way the experiment could be improved in order to increase the validity of the results. You have been assigned to design an experiment to determine the effects of light on the growth of tomato plants. In your experimental design be sure to: I. state one hypothesis to be tested II. identify the independent variable in the experiment III. identify the dependent variable in the experiment IV. identify 2 constants V. how will the control group be different from the experimental group VI. describe the type of data to be collected VII. draw a data table with two columns and label them appropriately Plants respond to their environment in many different ways. Design an experiment to test the effects of one environmental factor, chosen from the list below, on plant Growth. Acidity of precipitation Temperature Amount of water In your answer, be sure to: I. state one hypothesis to be tested II. identify the independent variable in the experiment III. identify the dependent variable in the experiment IV. identify 2 constants V. how will the control group be different from the experimental group VI. describe the type of data to be collected VII. draw a data table with two columns and label them appropriately Many plants can affect the growth of other plants near them. This can occur when one plant produces a chemical that affects another plant. Design an experiment to determine if a solution containing ground-up goldenrod plants has an effect on the growth of radish seedlings. In your experimental design be sure to: I. • state a hypothesis to be tested  II. • describe how the experimental group will be treated differently from the control group  III. • explain why the number of seedlings used for the experiment should be large  IV. • identify the type of data that will be collected  V. • describe experimental results that would support your hypothesis The photograph below shows a pill bug. Pill bugs are small animals frequently found in wooded areas near decomposing organic material. Describe some parts of an experiment to determine the preference of pill bugs for light or darkness. In your answer be sure to: I. state one hypothesis to be tested II. identify the independent variable in the experiment III. identify the dependent variable in the experiment IV. identify 2 constants V. how will the control group be different from the experimental group VI. describe the type of data to be collected VII. draw a data table with two columns and label them appropriately VIII.state one example of experimental data that would support your hypothesis A student conducted an experiment to determine if listening to different types of music would affect pulse rate. She thought that pulse rate would change with different types of music. Each person participating in her experiment listened to seven different selections of music for 30 seconds each. The pulse rates were taken after each 30-second interval of music. Based on her experiment, the student concluded that a person’s pulse rate changed when listening to different types of music. The component missing from this experiment is a (1) prediction (2) hypothesis (3) control group (4) research plan Students in a class recorded their resting pulse rates and their pulse rates immediately after strenuous activity. The data obtained are shown in the histograms below. I An appropriate label for the y-axis in each histogram would be (1) Number of Students (2) Average Number of Heartbeats (3) Time (min) (4) Amount of Exercise II. According to the data, compared to the average resting pulse rate, the average pulse rate immediately after strenuous activity generally (1) decreased (2) increased (3) remained the same (4) decreased and leveled off III. State one biological explanation for the fact that not all students had the same resting pulse rate. Base your answers to questions 44 through 47 on the data table below and on your knowledge of biology. The data table shows the number of fish species found at various ocean depths. Directions (44–45): Using the information in the data table, construct a line graph on the grid, following the directions below. 44 Mark an appropriate scale, without any breaks, on each labeled axis.  45 Plot the data from the data table. Surround each point with a small circle and connect the points.  46 State the general relationship between water depth and the number of fish species found.  47 The approximate number of fish species that can be found at 120 meters is (1) 5 (3) 18 (2) 13 (4) 31 A biology class conducted an experiment to determine the rate of respiration of yeast in bread dough at various temperatures. Bread dough will rise due to the production of carbon dioxide by the yeast present in the dough. An equal amount of dough was placed in the bottom of each of five graduated cylinders. Each cylinder was then placed in a different water bath to maintain a particular temperature. A diagram of the setup is shown below. The amount of expansion of the dough in each cylinder was measured after 15 minutes. The results are shown in the data table below. Using the information in the data table, construct a line graph on the grid, following the directions below. Mark an appropriate scale, without any breaks, on the axis labeled “Temperature of Water Bath (°C).”  Plot the data from the data table. Surround each point with a small circle and connect the points.  At which temperature did yeast cells produce the least amount of gas in 15 minutes?  _______________________°C Identify the independent variable in this investigation.  _______________________________________________________________________________________ Euglena are single-celled organisms that live in ponds. All euglena have chloroplasts and can make their own food. They can also take in food from the environment. The diagram below represents a euglena. An experiment was set up to determine the effect of nitrates, a pollutant, on the number of chloroplasts present in euglena. Five tanks were set up, each with euglena and a different concentration of nitrate solution: 0%, 0.5%, 1.0%, 1.5%, and 2.0%. The tanks were placed in a sunny location where each tank received the same amount of light. 31 Which statement is a possible hypothesis for this experiment that could be supported by the results of this experiment? (1) If the average number of chloroplasts in euglena decreases, will less nitrate be needed in each tank? (2) If the nitrate concentration is increased, then the euglena will have a lower average number of chloroplasts. (3) If the number of euglena in a tank increases, will more nitrates be produced? (4) If the nitrate concentration is decreased, then more light will reduce the average number of chloroplasts in euglena. 32 Which statement correctly identifies a variable in this experiment? (1) The independent variable is the concentration of nitrate solution used. (2) The dependent variable is the number of euglena placed in the tanks. (3) The independent variable is the amount of sunlight. (4) The dependent variable is the number of tanks used. 33 Euglena can be classified as both (1) an autotroph and a parasite (3) a producer and a parasite (2) a decomposer and a heterotroph (4) an autotroph and a heterotroph Which individual most likely has diabetes? (1) A (3) both A and B (2) B (4) neither A nor B 48 Identify one hormone associated with the maintenance of blood glucose levels.  __________________________________ _________ Key = Individual A = Individual B Blood Glucose (mg/100 mL) Time (hr) table below and on your knowledge of biology. Diabetes is a disease characterized by consistently high blood glucose levels (at or above 126 mg/100 mL) as a result of hormone deficiency. For a study of diabetes, blood glucose levels from individual A and individual B were recorded each hour over a 5-hour period following a meal. The results are shown in the data table below. Blood Glucose Levels (mg/100 mL) Directions (44 – 46): Using the information in the data table, construct a line graph on the grid on the next page, following the directions below. 44 Mark an appropriate scale, without any breaks, on each labeled axis.  45 Plot the data for individual A on the grid, surround each point with a small circle, and connect the points.  46 Plot the data for individual B on the grid, DNA samples can be separated according to size using the technique of (1) chromatography (3) replication (2) electrophoresis (4) dissection The diagram below represents the results of a laboratory procedure. This procedure is used to (1)separate molecules in a liquid mixture (2)detect glucose in a solution (3)determine the rate of photosynthesis in plants (4)examine the gene sequences of organisms A student performed a gel electrophoresis experiment. The results are represented in the diagram below. Compared to the fragments at the top of the gel, the fragments at the lower end are (1) larger, and move slower (2) smaller, and move faster (3) larger, and move faster (4) smaller, and move slower Reasons for conducting peer review include all of the following except (1) analyzing the experimental design (2) pointing out possible bias (3) identifying an illogical conclusion (4) changing data to support the hypothesis The drawings below were made during a laboratory exercise in which a microscope was used to view slides of preserved protozoa. The microscope had a 10× eyepiece and two different objectives. 81 Which statement about the size of the organisms is correct? (1) Organism A is larger than organism B. (2) Organism B is larger than organism A. (3) Organisms A and B are both the same size. (4) The relative size of the organisms cannot be determined from the information given. New varieties of organisms have resulted from human activities. These organisms have often led to problems in modern society. Two of these new varieties are listed below. Antibiotic-resistant bacteria Pesticide-resistant insects 56–60 Select one of these varieties and discuss a problem associated with the development of this new variety of organism. In your answer, be sure to: • identify the variety you selected • identify one biological process by which a population of this variety may develop resistance  • describe how this process is involved in the production of a population of resistant organisms  • identify one problem caused by this resistance  • state one solution to this problem  • identify one possible negative effect of this solution  Variety: The diagram below represents the measurement of a biological specimen. What is the approximate length of the specimen in millimeters? (1) 25 mm (3) 35 mm (2) 30 mm (4) 40 mm The diagram below shows a student heating some test tubes with chemicals in them during a laboratory activity. Explain why putting stoppers in the test tubes could be dangerous.  ______________________________________________________________________ _________________ ______________________________________________________________________ _________________ The materials represented in the diagram below were used in a laboratory activity. These materials were used to carry out the technique known as (1) DNA staining (3) paper chromatography (2) genetic engineering (4) glucose testing A coverslip should be slowly lowered from a 45° angle onto a slide in order to (1) prevent the slide from being scratched (2) stop the loss of water from under the coverslip (3) ensure that the specimen being viewed will stay alive (4) reduce the formation of air bubbles An experiment was designed to test whether students could squeeze a clothespin more times in 1 minute after resting or after exercising. What would be a hypothesis for the experiment? (1) Do students squeeze clothespins more often in 1 minute after exercising? (2) Can most students squeeze a clothespin more times after they rest? (3) Ten students who exercise before squeezing a clothespin squeezed it more times in 1 minute than ten students who rested first. (4) Students who rest before squeezing a clothespin will squeeze it fewer times in 1 minute than students who exercise beforehand. An experiment was designed to test whether students could squeeze a clothespin more times in one minute after resting or after exercise. Note: The answers to questions 81 and 82 should be recorded on your separate answer sheet. 81 The dependent variable for this experiment is the (1) time the student was squeezing the clothespin (2) number of times the student was able to squeeze the clothespin (3) strength of the student (4) length of the clothespin 82 The experimental results could be made more valid by (1) increasing the number of students (3) using safety precautions (2) using a plastic clothespin (4) making a bar graph of the data A chemical known as fertex affects external fertilization of sea urchin eggs. An experiment was set up using three tanks to investigate the effect of fertex. Each tank had a different concentration of fertex: 1%, 2%, and 3%. Ten sea urchin eggs and 2 mL of sea urchin sperm were added to each of the three tanks. A fourth tank was set up as a control. State one way the contents of the control tank would differ from the contents of the three experimental tanks. Identify two factors that must be kept the same in all four tanks. Factor 1: Factor 2: State one way to improve the validity of the experimental results. Identify the independent variable in the experiment. State one example of the type of data that should be collected during the experiment. An experiment was carried out to determine whether drinking caffeinated soda increases pulse rate. The pulse rates of two groups of people at rest were measured. Group A was then given caffeinated soda and group B was given caffeine-free soda. One hour after drinking the soda, the pulse rates were measured. The participants in the experiment were all the same age, and they were all given the same amount of soda. The dependent variable in this experiment is the (1) type of soda given to each group (2) amount of soda given to each group (3) pulse rate of each group (4) age of participants in each group Blown Away Head Lice Meet Hair Dryer of Death Head lice are becoming indestructible. A study found that as many as 80 percent of the bugs are [resistant] to insecticides in over-the-counter shampoos, and resistance will only increase. Evolutionary biologist Dale Clayton may have a new line of attack. Clayton, who usually studies lice on bird feathers, stumbled onto his solution after a major research setback. When he moved his laboratory from England to the University of Utah a decade ago, his entire louse collection perished in the dry desert air. Soon after, his 8-year-old came home from school with head lice. He wondered if human head lice could also be killed by drying them out. “It was sort of a forehead slapper,” Clayton says. After conventional hair dryers failed, Clayton came up with the LouseBuster, a 10pound device resembling a vacuum cleaner that desiccates [dries out] the bugs with a jet of 140-degree air [140°F]. “It’s a pretty brutal assault,” he says. Tests show the invention is both safe and effective, eradicating 80 percent of live lice and 98 percent of eggs, leaving survivors unable to breed. And, Clayton says, “it will be awfully hard for lice to develop resistance.” Source: Emily Saarman, “Blown Away—Head Lice Meet Hair Dryer of Death,” Discover Magazine, February 2007 I. State how Clayton first learned that desiccating lice kills them.  II. state the hypothesis to be tested in the experiment  III. state one way the control group will be treated differently from the experimental group  IV. state one result of the experiment that would support the hypothesis  Daphnia (water fleas) are sensitive to many changes in pond ecosystems. For this reason they are often used in bioassays, tests in which organisms are exposed to various levels of a chemical to determine what levels are safe. The results of these tests determine whether or not the chemical being tested will affect other pond organisms. An experiment was designed to determine the toxicity of different salt solutions on cultures of daphnia. Five fish tanks were each filled with the same amount of water containing different concentrations of salt. Ten daphnia were placed into each tank. After 48 hours, the number of daphnia that had survived and the number of daphnia that had died in each tank were recorded and the percent mortality was calculated. The results of the experiment are shown in the data table below. Using the information in the data table, construct a line graph on the grid on the next page, following the directions below. I. Label the x-axis. Be sure to include units. II. Mark an appropriate scale, without any breaks, on each axis. III. Plot the data for mortality on the grid. Surround each point with a small circle and connect the points. IV. Which salt concentration was most toxic to the daphnia in this experiment? (1) 1.25 g/L (3) 5.0 g/L (2) 2.5 g/L (4) 10.0 g/L V. Which salt concentration is most likely closest to the concentration of salt found in the natural environment of this species of daphnia? Support your answer. Salt concentration:_______________________ Base your answers to questions 48 and 49 on the graph below and on your knowledge of biology. The graph shows the number of species that became extinct from 1800 to 2000. It also shows estimates of the number of species that will become extinct between 2000 and 2020. The number of species that became extinct between the years 1950 and 2000 is approximately (1) 5,000 (3) 22,000 (2) 12,000 (4) 37,000 Five students design an experiment to answer the question: “How is heart rate affected by running?” Two chairs were set up at different ends of a large room. The pulse rate of each student was taken at rest just before running. Each of the five students ran between the chairs a different number of times. Their pulse rates were taken after running and the results are shown in the table below. If a control group is not included in an experiment, it would be difficult to (1) formulate a hypothesis for the experiment (3) record data in a data table (2) make observations about the experimental group (4) draw a valid conclusion The bar graph below shows the height of a plant at the end of each week of a fiveweek growth period. Which statement represents a valid conclusion based on the information in the graph? (1) The plant was given water during the first three weeks, only. (2) The plant will grow faster during the sixth week than it did during the fifth week. (3) The plant grew fastest during the first three weeks, and then it grew slower. (4) The plant grew slowest during the first three weeks, and then it grew faster. When using a compound light microscope, the most common reason for staining a specimen being observed is to (1) keep the organism from moving around (2) make the view more colorful (3) determine the effects of chemicals on the organism (4) reveal details that are otherwise not easily seen Thrips are insects that feed on the pollen and flowers of certain plants. The size of a thrip populationdepends on the number of flowers available. Which graph best represents changes in a population of thrips if winter was longer than usual and the summer was too cool and dry for many flowers to bloom?