Answers
Chapter 1
Formative Practice 1.1 page 6
1. Goggles/lab coat/face mask/gloves/
covered shoes/safety shoes (any three)
2. Rinse his eyes with plenty of water and
report to the teacher.
3. (a) Amardev wears goggles when
✓
mixing acid and water.
(b) Aqil wears slippers while
carrying out an experiment.
(c) Mira cleans the spilled
chemical substance on the
laboratory table by using her
hands.
Formative Practice 1.2 page 10
1. Yes, because concentrated hydrochloric
acid with a pH value of 3 will cause
danger.
✓
2. Distilled water
Concentrated acid
Radioactive substance
3. The carcasses need to be wrapped in
an absorbent material (tissue paper),
carefully wrapped in a biohazard plastic
bag and frozen. The container or bag
needs to be stored in a cold temperature
such as in the refrigerator or a freezer
room until it is taken by the selected
contractor.
4. (i) Inform the teacher or the laboratory
assistant immediately.
(ii) Make the spillage area a restricted
zone.
(iii) Sprinkle some sulphur powder onto
the spillage.
(iv) Call the Fire Department.
Formative Practice 1.3 page 14
1. Water-type fire extinguisher/foam-type
fire extinguisher/carbon dioxide-type fire
extinguisher/dry powder fire extinguisher/
ABC fire extinguisher (any four)
2. Function: extinguishes small or moderate
fire that is difficult to extinguish with
water.
Method: Wrap the victim’s body to
prevent contact with oxygen that aids the
combustion process.
3. R, Q, P
Summative Practice 1 page 16 – 17
1. (a) Laminar flow cabinet/fume chamber/
safety shower/eyewash station
(any three)
(b) There are dangerous substances in
the laboratory that are flammable,
corrosive, toxic and fragile.
(c) His action is correct because lemon
juice contains a pH value of more
than 5 and less than 7.
2. (a) (i) Class B fire
(ii) Foam/dry powder/carbon dioxide
(b) • Ethanol is very close to the fire
source and the conditions needed
for combustion are present.
• Ethanol is a flammable and volatile
substance.
(c) • Use the fire extinguisher
1. Pull the safety pin from the fire
extinguisher.
2. Aim the nozzle at the base of
the fire. He should be 2.0 – 2.5
metres away from the fire.
3. Squeeze the handle on top of the
fire extinguisher.
4. Spray evenly on the entire fire
source by sweeping the nozzle
from side to side.
• Use the fire blanket
(d) (i) Types of fire extinguishers
1
(ii) Expiry date of fire extinguishers
(iii) Pressure reading on fire
extinguishers
(iv) Number of fire extinguishers
based on types
(v) Location of the fire extinguishers
in the school’s emergency route
plan
Mind Challenge page 17
3. No.
The face mask needs to be worn only
when mixing chemical substances
that are volatile, pungent and when
handling chemical substances that are
concentrated.
4. Haziq needs to wear suitable
self-protection equipment and make
sure that he handles the beaker and
thermometer carefully. Haziq also
needs to ensure that all the flammable
substances are not close to the Bunsen
burner.
5. Sharp objects need to be stored in a
special container (sharps wastes bin)
for sharp residues. The container needs
to be closed neatly and must not be
filled more than ¾ of its capacity. The
container is stored at a safe place and
must be disposed of by the selected
contractor.
Chapter 2
Formative Practice 2.1 page 24
1. An emergency aid that involves a
combination of chest compressions and
breathing into the mouth of the victim.
2. • Heart attack
• Electric shock
• Lightning strike
• Drowning
(any three)
3. Yes, he can. Chest compression
technique is the most suitable method
for someone who has a heart attack.
This method is carried out to restore
blood circulation artificially by pumping
2
blood through the heart. Muthu's dad will
survive if the flow of blood continues in
his body.
4. No. This is because if the wrong
technique is used, the victim may be
injured. The correct way to help the victim
is to check the victim’s response, shout
‘help’, call 999 and wait until the victim
gets emergency treatment.
Formative Practice 2.2 page 28
1. An emergency help that is carried out to
save a choking victim.
2. Amirul needs to help his grandfather by
performing the Heimlich Manoeuvre.
Firstly, Amirul needs to stand behind his
grandfather and bend his grandfather’s
body slightly forward. Then, he needs to
put his hands around his grandfather’s
waist and clench a fist with his right
hand. The right fist is put between his
grandfather’s navel and ribs. The left
hand is put on top of his right fist. Next,
he needs to press and jerk upwards
with quick force. The pressure given will
increase the pressure in his grandfather’s
lungs, causing the foreign object to be
ejected.
3. We can give emergency help to choking
victims so that oxygen can reach the
brain to avoid brain damage and death.
Summative Practice 2 page 30 – 31
1. (a) P: Cardiopulmonary resuscitation,
CPR
Q: Heimlich Manoeuvre
(b) The victims will experience brain
damage because they do not receive
sufficient oxygen in their body and
brain for a certain period.
2. (a) CPR
(b) Position the victim's body on his side
and wait for the ambulance to arrive.
3. (a) The victim will choke.
(b) The Heimlich Manoeuvre will
increase the pressure in the lungs
causing the food to be ejected.
(c) Yes. To help a pregnant woman using
this method, place your hands right at
the bottom of the breastbone, a little
bit higher than on a non-pregnant
woman. Then, proceed with the usual
Heimlich Manoeuvre.
4. (a) The Heimlich Manoeuvre
(b) Firstly, one of Jia Hui’s friends needs
to stand behind Jia Hui and bend her
body slightly forward. Then, place
her hands around Jia Hui's waist and
clench a fist her right hand. The right
fist is put between Jia Hui's navel
and ribs. Her left hand is placed on
top of her right fist. Next, she needs
to press and jerk upward with quick
force until the food is ejected out of
Jia Hui’s mouth.
Mind Challenge page 31
5. (a) To choose a first aid method to be
given to a person who suddenly
collapsed and became unconscious.
(b) CPR is performed if Saiful is not
breathing and there is no pulse. The
Heimlich Manoeuvre is performed if
he is conscious and suffocating.
(c) CPR, Heimlich Manoeuvre
(d) • CPR
• CPR is an emergency aid or
treatment to be given to someone
who suddenly collapses and is
not breathing or when no pulse is
detected.
Chapter 3
Formative Practice 3.1
1.
Clinical
thermometer
Measures body
temperature at
the armpit, ear or
under the tongue
page 37
Rectal
thermometer
Measures body
temperature
through the rectum
(accept any relevant answers)
2. Infection, exposure to extreme heat,
exercise
3. Refer to the doctor.
Experiment 3.1
page 38 – 39
A
Question:
Yes, females have a higher pulse rate than
males.
B
Question:
Yes, the pulse rate of the older sample is
lower.
C
Question:
1. The pulse rate increases when running
because the heart needs to pump more
blood to supply more oxygen to the body.
2. No, because the pulse rate depends
on the level of fitness and health of the
student.
Formative Practice 3.2 page 40
1. Pulse rate is the measurement of the
number of heartbeats per minute.
2.
✓
3. No. Pregnant women have a higher pulse
rate because their hearts need to pump
more blood to supply sufficient oxygen
and nutrients to the foetus.
4. No. The pulse rate will increase after
doing physical activities. This is because
the heart needs to pump more blood to
supply more oxygen to the body.
Formative Practice 3.3 page 42
1. Blood pressure is the pressure applied
by the blood to the wall of blood vessels
during blood circulation.
2. Sphygmomanometer
3. The patient needs to be relaxed and
calm. He needs to seat upright. Put the
3
patient's arm on the table and put the
sphygmomanometer cuff on the patient’s
upper arm. Take the reading after hearing
the ‘beep’ sound.
4. It can cause serious illnesses especially
stroke.
5. • Eat a balanced diet
• Exercise regularly
• Always think positive
• Check blood pressure regularly and
consistently
• Manage stress
Formative Practice 3.4 page 44
1. Body mass ratio compared to height
2. It can prevent the possibility of getting
serious illnesses
3. Obesity/overweight
4. Increases the risk of suffering from
serious illnesses such as heart attack,
high blood pressure, stroke, diabetes
mellitus and cancer.
5. No. Being underweight also increases
the risk of acquiring health problems
such as heart diseases, decrease in the
body’s defence against diseases, fatigue,
anaemia and depression.
Summative Practice 3 page 46 – 48
1. (a) Infection, exposure to extreme heat,
vigorous exercise
(b) 36.9°C
(c) Infrared thermometer/rectal
thermometer
2. (a) P : Infrared thermometer
Q : Rectal thermometer
(b) To measure body temperature
(c) Infrared thermometer
(d) Can cause death (accept any suitable
answers)
3. (a) 100 – 150
(b) Manipulated variable: the age
Responding variable: the pulse rate
(c) When the age increases, the pulse
rate decreases.
(d) 60 – 65 beats per minute
4
4. (a) The wrist
(b) 60 – 65 beats per minute
(c) 120/80 mmHg
(d) Fareeza must do health check-ups
regularly at the clinic or hospital
(accept any suitable answers)
5. (a) 120/80 mmHg
(b) The reading of Siva’s blood pressure
is higher than a normal person
because he may have high blood
pressure.
(c) Siva needs to go to the hospital to get
proper treatment.
(accept any suitable answers)
6. (a) Organ damage
(b) Sphygmomanometer
(c) Systolic pressure is the blood
pressure when the heart muscles
contract. Diastolic pressure is the
blood pressure when the heart
muscles are resting.
Mind Challenge page 48
7. Yes. The rectal thermometer is usually
used on children below 3 months old.
Rectal thermometer can also be used on
adults to get a more accurate reading.
8. (a) Heart attack, high blood pressure,
stroke, diabetes mellitus,
complications of joints and bones
(b) Nur Antasya can lose her weight by
trying out the following steps:
(i) Weigh herself once a week
(ii) Eat healthy foods moderately
based on the food pyramid
(iii) Make changes to her eating
habits
(iv) Reduce/avoid foods that are high
in sugar and fat
(v) Do moderate exercises such
as brisk walking, cycling and
swimming
9. The right food to eat is an egg sandwich.
This is because egg sandwiches contain
low fat. To lose weight, Marissa needs to
reduce fatty and sugary foods.
Chapter 4
Formative Practice 4.1 page 55
1. The development and application of
products, equipment and systems used
to conserve the environment and nature,
as well as minimising and reducing the
negative effects of human activities.
2. • Saves energy
• Strengthens the country’s economy
3. • Energy sector
• Waste and wastewater management
sector
• Agriculture and forestry sector
• Transportation sector
• Building sector
• Industrial and manufacturing sector
• Information and communications
technology sector
(accept any suitable answers)
Formative Practice 4.2 page 60
1. • Increase in the use of fossil fuel
• Extreme climate change
• Increase in greenhouse gases
2. • Organise an energy efficiency practice
campaign
• Practise and implement Green
Technology
Formative Practice 4.3 page 61
1. • Leftover food is not well disposed of
• Chemical waste and trash are disposed
of into the river and sea illegally
2. • Practise of 5R, which is Refuse,
Reduce, Reuse, Recycle and Recovery
• Practise garbage sorting
Formative Practice 4.4 page 65
1. Uncontrolled logging
2. Chemical fertilisers seep into the soil
and reach water sources like rivers. As a
result, the water in the river is polluted. In
addition, the acidity of the soil increases.
3. • Organise a recycle campaign
• Save on paper usage
• Control and limit logging activities
Formative Practice 4.5 page 68
1. The uncontrolled increase in greenhouse
gases contributes to the greenhouse
effect
2. fatty acid methyl ester, plant oils,
animal fats
Formative Practice 4.6 page 69
1. • Mariam's activity can reduce global
warming. The plants absorb carbon
dioxide during photosynthesis and
release oxygen. The more the trees,
the higher the amount of carbon
dioxide plants can absorb.
• Carpooling is good for reducing the
emission of carbon dioxide by vehicles.
This can reduce the greenhouse effect.
2. Greenhouse gases decreases, nature
is protected, prevents extreme climate
change
Summative Practice 4 page 71 – 73
1. (a) The development and application of
products, equipment and systems
used to conserve the environment
and nature, as well as minimising
and reducing the negative effects of
human activities.
(b) Energy, environment, economy,
social
2. (a) Saves energy, avoids wastage,
strengthens the country’s economy
(b) Switch off the electrical appliances
when they are not in use. This can
save energy consumption at home.
3. (a) Energy sector, transportation sector,
waste and wastewater management
sector
(b) Energy sector – focuses on the use of
a cleaner and carbon-free alternative
energy that can replace the use of
fossil fuels.
Transportation sector – focuses
on the improvement of a cleaner
transportation infrastructure, vehicle
fuel and public transportation.
5
Waste and wastewater management
sector – focuses on minimising waste
disposal and wastewater into the
environment by converting waste or
wastewater into something new such
as compost.
4. (a) • Global warming
• Increase in greenhouse gases
• Acid rain
(b) • Use renewable energy
• Practise energy efficiency
(c) Prevents global warming/reduces
carbon dioxide production in the air/
prevents acid rain
(d) I agree, because the practice of
Green Technology can reduce the
dependence on fossil fuel energy
sources, thus can reduce air pollution
due to the release of carbon dioxide
from the burning of fossil fuels.
5. (a) Transportation sector – focuses
on the improvement of a cleaner
transportation infrastructure, vehicle
fuel and public transportation
(b) Using solar-powered vehicles,
carpooling, cycling
Mind Challenge page 73
6. Suggestion: Modify a cardboard roller
into a mini nursery. Fold one of the open
sections of the cardboard roller so that it
is closed. Scatter the seeds and sprinkle
them with enough water.
Cut
Fold
Soil
(Or any suitable method)
6
Chapter 5
Formative Practice 5.1 page 83
1. (a) A gene is a basic hereditary unit
that determines an individual’s
characteristics.
(b) Chromosomes are fine thread-like,
long and spiral structures located in
the nucleus.
(c) Deoxyribonucleic acid or DNA is a
two twisted antiparallel polynucleotide
chain forming a structure known as
double helix.
2. Mitosis takes place in the somatic
cell and meiosis takes place in the
reproductive organ.
3. (Refer Figure 5.7, page 82 of the
textbook, the double bubble map shows
the similarities and differences between
mitosis and meiosis)
Formative Practice 5.2 page 89
1. Dominant allele would show the
characteristics that it controls and hides
the effects of the recessive allele. The
recessive allele would only show the
characteristics it controls when the
dominant allele is absent.
2. Sex chromosomes are chromosomes
that determine a person's gender. Sex
chromosomes consist of two types,
X and Y.
3. The sex chromosomes of the father. If the
sperm (22+X) fertilises the ovum (22+X),
the gender of the child is female (44+XX).
If the sperm (22+Y) fertilises with the
ovum (22+X), the gender of the child is
male (44+XY).
Formative Practice 5.3 page 100
1. Mutation is a change that occurs
spontaneously and randomly on the
genes or chromosomes, which can
cause a characteristic change in the child
inheriting the modified genetic materials.
2. Radioactive radiation, X-ray and toxic
chemical substances.
3. Advantages of genetic research:
(i) Improves the quality of human
life such as in the field of forensic
science, gene therapy and genetic
genealogy.
(ii) Genetic research helps to increase
the yields in a short time.
Disadvantages of genetic research:
(i) Unethical genetic modification such
as making biological weapons that
can harm humans.
(ii) Genetic research that produces
new species will cause the original
species to become extinct.
4. Human life and the environment will be
threatened.
Formative Practice 5.4 page 103
1. Genetic engineering is a genetic
modification process of an organism.
2. Meaning:
(i) Recombinant DNA is a technology
that combines genetic materials from
two different species to produce a
new gene.
Example: DNA from a human is
combined with bacterial DNA to
produce a hybrid DNA for insulin
production.
(ii) Gene therapy is a technique that
is used to repair mutated genes
(abnormal or deformed) responsible
for diseases such as cystic fibrosis,
haemophilia and sickle cell anaemia.
(iii) GMO is an organism (plant, animal,
bacteria or virus) which has been
genetically modified for a particular
purpose. For example, production
of genes that can kill insects and
applied to plantations of paddy, maize
and palm oil.
3. Three advantages and disadvantages
of genetic engineering technology to
humans.
Advantages:
• identify, diagnose and treat hereditary
diseases.
• better quality crops and farm animals
can be produced.
• crops and farm animals that have high
resistance to diseases.
Disadvantages:
• cloning will cause moral, ethical and
religious issues such as cloning of
humans.
• produces organisms that have high
resistance to medicine because the
organism’s genes have been mutated
by genetic changes.
• can cause side effects to the user
because the genetically modified gene
will integrate with the user’s genes.
Activity 5.8 page 105 – 106
1. (depends on the results of the activity
carried out)
2. Both histograms display bell-shaped
curves.
3. There is no distinct difference
Activity 5.9 page 106
1. Discrete shape
2. Yes
Formative Practice 5.5 page 108
1. Variation is the characteristic differences
between individuals of the same species.
2. (a) Continuous variation and
discontinuous variation.
(b)
Continuous
variation
Similarity
Discontinuous
variation
Both occur in the same species
Differences
Aspects:
Not distinct
Difference
between
individuals
Distinct
Normal
distribution
Graph
shape
Discrete
Genetic and
environment
Factors
affecting
Genetic only
7
3. Two genetic factors that cause variation:
• Crossover between homologous
chromosomes during meiosis enables
genetic exchange.
• Independent chromosome arrangement
produces gametes that have different
genetic information.
(Refer Figure 5.30, page 107 in
textbook - any two genetic factors)
4. Example: skin colour
• The same individual can have different
skin colour in two different locations.
5. Three importance of variation:
• Variation allows natural selection.
• Variation helps organisms to
camouflage to protect themselves from
predators.
• Variations in animals and plants
increase their value
Summative Practice 5 page 110 – 111
1. (a) (i) DNA (deoxyribonucleic acid)
(ii) Deoxyribose sugar, phosphate
group, nitrogenous base
(b) 46
(c) Autosomes carry genes that control
the characteristics of organisms such
as the colour of pupil, ability to roll
the tongue and types of hair, while
sex chromosomes carry genes that
determine the gender of an organism
whether male or female.
2. (a) Prophase I
(b) Chromosomes shorten and
thicken, and become clearly visible.
Homologous chromosomes pair
together. Crossing over occurs.
(c) The process that occurs is crossing
over. Crossing over produces a new
genetic combination. If crossing over
does not happen, no variation is
formed.
(d) Reproductive cells
3. (a) Prophase
(b) Chromosomes are arranged in an
equatorial plane. The spindle fibres
are attached to the centromere.
8
(c) Humans: skin, Plants: shoot/root
Mind Challenge page 111
4. (a) • Mrs K is pregnant at the age of 35
and above.
• Mrs K is exposed to radioactive
radiation.
(b) (i) Down syndrome
(ii) Male
Chapter 6
Activity 6.2
1.
page 117
Length (cm)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Day
2. The growth curve is shaped like that
because the animals with exoskeleton
undergo several stages of ecdysis before
reaching adulthood.
3. On days 1 – 5, the insect is in the instar
stage, in which no growth occurs. At
the end of day 5, the insect inhales air
to expand its body. Therefore, there is
an increase in the length of the insect.
On days 6 – 10, the insect undergoes
the instar stage again until the end
of day 10 where the second ecdysis
process occurs. The length of the insect
increases. Ecdysis process occurs again
on day 15, on day 20, on day 25 until the
insect reaches its adult size.
Experiment 6.1 page 125
Questions:
1. (a) Hollow bone
(b) Compact bone
2. • Lighter and stronger
• Allows animals to move faster
Formative Practice 6.1 page 128
1. Support system is important to ensure
that animals are able to move smoothly
and efficiently.
2. The exoskeleton is a frame made of waxy
chitin or shell. The endoskeleton is a
skeleton made up of bones or cartilages.
Hydrostatic skeleton is a skeleton
consisting of muscular walls covering a
certain body cavity filled with fluid.
3. The growth curve of exoskeleton animals
is in stages. The exoskeleton is made
up of wax chitin that is hard and cannot
expand. Therefore, the growth of animals
is hindered. To overcome this problem,
exoskeleton animals will moult a few
times to reach adulthood.
4. Ecdysis is a process where animals with
exoskeleton shed their outer layer shell
during growth.
5. Centre of gravity and base area
6. (a) Centre of gravity refers to the point
of equilibrium of animals, plants or
objects.
(b) The higher the position of an object,
the higher the centre of gravity. A
higher centre of gravity causes an
object to be less stable.
Formative Practice 6.2 page 133
1. Two parameters used to measure human
growth rate:
• mass
• height
2. The male growth rate is different from the
female growth rate.
From infant stage to childhood: Growth is
the same.
At 4 years old: Males grow more rapidly
At 12 – 14 years old: Females grow more
rapidly.
After 14 years old: Males grow more
rapidly.
3. Diet affects an individual’s growth. A
balanced diet provides sufficient nutrients
for cell growth and cell division.
4. Growth rate can be measured using a
height or body mass parameter. The
graph of height or body mass against
time can be plotted to observe the growth
rate.
Experiment 6.2 page 137
Questions:
1. The plotted graph does not show a
sigmoid shape. This is because the
period of experiment is too short.
2. As the time (day) increases, the height of
the green bean sprout increases too.
Formative Practice 6.3 page 137
1. To stand upright to get sunlight.
2. Woody plants have woody stems and
roots such as buttress roots, prop roots
and stilt roots. Non-woody plants have
support from cell turgidity, tendrils and
clasping roots. Aquatic plants depend on
hollow stem and buoyancy of water for
support.
3. Herbaceous plants are non-woody plants.
They are supported by cell turgidity.
Summative Practice 6 page 139
1. (a) (i) Tendon
(ii) Tendons connect muscles to
bones.
(iii) Tendons consist of a combination
of tough and inelastic fibres.
(b) The individual cannot move the
bone because the force generated
by muscle contraction cannot be
transferred to the bone.
(c) Tendon is a structure that connects
muscles to the bone while ligament
is a structure that connects bone to
bone.
2. (a) Hydrostatic skeleton
(b) Longitudinal muscle and circular
muscle
(c) Movement in the earthworm occurs
when the longitudinal muscles
contract and the circular muscles
relax in opposition. This opposite
9
movement creates movement
from the front to the rear of the
earthworm's body. The earthworm
also has chaetae (bristle-like hairs)
on its body to grip the ground during
movement.
3. (a) (i) The giraffe will spread its legs.
(ii) This will increase the base area
of the giraffe and lower its centre
of gravity
(b) (i) X
(ii) Animal X has a lower centre of
gravity.
(iii) When sitting down.
4. Woody plants have big and tall stems. To
increase the stability of woody plants, the
plants need to increase their base area.
Therefore, woody plants have additional
support such as buttress roots, prop roots
and stilt roots to increase their base area.
Mind Challenge page 141
5. (a) Cannot
(b) The whale’s body is supported by
small internal skeletons. These
skeletons cannot support the weight
of the whale that is stranded on the
beach. Whales are supported by
the buoyancy of water to help their
movements in the sea. Shallow
seawater near the coast is not
enough to provide the necessary
buoyancy to allow whales to return to
the sea.
Chapter 7
Formative Practice 7.1 page 152
1. A hormone is an organic chemical
compound secreted by the endocrine
gland.
2. The main endocrine glands in the human
body are pituitary gland, thyroid gland,
adrenal gland, pancreas, ovary and
testis.
3. Adrenal gland: adrenaline
10
Pancreas: insulin
Testis: testosterone
Thyroid gland: thyroxine
4. Functions of hormones:
(a) Thyroid gland: Thyroxine – controls
the rate of metabolism
(b) Ovary: Progesterone – maintains the
thickening of the uterine wall
Oestrogen – controls the female
secondary sexual characteristics
(c) Pancreas: Insulin – controls the blood
glucose level
Formative Practice 7.2 page 157
1. Imbalance of hormone, unclear speech
and slow reflex action.
2. The movement of nerve impulses within
neurons is disrupted (fast or slow).
3. Chemicals in drugs and alcohol delay
the transmission of information to the
endocrine gland to secrete the hormones
the body needs.
Formative Practice 7.3 page 161
1. The mind is a brain function related to
our consciousness such as personality,
thoughts, memory, judgement, intellect
and emotion.
2. Five characteristics of a healthy mind:
• Can think and make reasonable
decisions
• Can detect stimuli and respond
appropriately
• Can remember the sad and happy past
events
• Can distinguish between right and
wrong
• Be open-minded and not be emotional
3. Hormonal imbalance affects mental
health. Over secretion and under
secretion of hormones by endocrine
glands cause imbalance in body function.
For example, a woman with premenstrual
syndrome has an imbalance in oestrogen
and progesterone hormone secretion
by the ovary. The hormonal imbalance
causes the woman to become irritable,
have headache and become depressed.
4. • Excessive intake of alcohol
• Drug abuse
• Aging
Summative Practice 7 page 163 – 164
1. (a) P – Pituitary gland
(b) (i) Thyroxine
(ii) • Low metabolic rate
• Stunted mental and physical
development in children
(cretinism)
• Lack of energy in adults
(myxedema)
• Tend to be obese
• Have goitre
(c) (i) Pancreas
(ii) Insulin
(iii) • Less insulin hormone is
secreted
• Blood glucose is not able to
be converted to glycogen.
• This causes the blood glucose
level to rise.
(d) Testosterone hormone
2. (a) (i) Oestrogen, progesterone
(ii) 1. Promotes the development
of female secondary sexual
characteristics
2. Prepares the uterus for
implantation of embrio
(b) After puberty
(c) (i) Testis
(ii) Controls the development
of male secondary sexual
characteristics such as
enlargement of the voice box
and hair growth on their face.
Mind Challenge page 164
3. Coffee contains caffeine which is
dangerous if taken excessively.
4. Alcohol that enters the foetus through
the placenta can cause various disorders
to the foetus such as Foetal Alcohol
Spectrum Disorder (FASD). The foetus
may experience disabilities or abnormal
formation of the face along with various
other disabilities, growth failure and
disruption of the function or structure of
the central nervous system.
5. Advise her to speak to the counseling
teacher.
Chapter 8
Formative Practice 8.1 page 170
1. Atoms, molecules and ions
2. Rust
3.
Atom
Molecule
4.
Ion
Iron
sheets
Ice
cubes
Common
salt
Copper
wire
Sugar
cubes
Marbles
Helium
gas
Oxygen
gas
Limewater
Element
Atom
Molecule
Carbon
Carbon
rod
Carbon
dioxide
Sulphur
Sulphur
powder
Sulphur
dioxide
Formative Practice 8.2 page 174
1. (a) Group 1, Period 2
(b) Group 11, Period 5
(c) Group 18, Period 1
(d) Group 11, Period 6
2. Fluorine/chlorine/bromine/iodine/astatine
(any two)
3. Potassium
4. 2.8.5
5. • Negative ions are formed when atom of
an element accepts electrons from the
atom of other elements. For example,
chlorine atom accepts one electron
from the atom of another element to
form chloride ion.
• Positive ions are formed when the atom
of an element donates electrons to the
11
atom of another element. For example,
sodium atom donates one electron to
the atom of another element to form
sodium ion.
Activity 8.6
Isotope
page 175
Number Number
Nucleon
of
of
number
protons neutrons
Chlorine-35
17
18
35
Chlorine-37
17
20
37
Sodium-23
11
12
23
Sodium-24
11
13
24
Bromine-79
35
44
79
Bromine-81
35
46
81
Formative Practice 8.3 page 177
1. Two or more atoms of an element which
have atoms with the same number of
protons but different number of neutrons.
2. Sodium-24/Phosphorus-32/Cobalt-60/
Carbon-14/Iodine-131
(any three)
3. 20
4. • Cobalt-60: kills cancer cells
• Sodium-24: detects clogged blood
vessels
• Iodine-131: detects the rate of iodine
absorption by the thyroid gland and it is
used to treat thyroid disease
Summative Practice 8 page 179 – 181
1. (a) (i) Salt: ions
(ii) Sugar: molecules
(b) Ions: marbles/limewater/acid/alkali
Molecules: carbon dioxide/oxygen/
nitrogen/naphthalene/alcohol
(c) Molecules: oxygen gas/carbon
dioxide gas/sulphur dioxide gas
Ions: zinc oxide/iron oxide
2. (a) The elements are arranged from left
to right and top to bottom, in the order
of their increasing proton numbers.
(b) P and U
12
(c) Element R.
Element R has achieved a stable
octet electron arrangement.
(d) Group 16, Period 3
(e) (i) P: 2.1
(ii) Q: 2.7
(iii) T: 2.8.3
3. (a) X: 14
Y: 18
Z: 20
(b)
Atom X
Atom Y
Atom Z
(c) X: Group 13, Period 3
Y: Group 17, Period 3
Z: Group 2, Period 4
(d) (i) Atom X will donate three
electrons to the atom of another
element to form a positive ion.
(ii) Atom Y will accept one electron
from the atom of another element
to form a negative ion.
4. (a) Q and R, because atom Q and R
have the same proton number but
different nucleon number.
(b) Industry: is used to detect leakage in
underground pipes
Medical: detect clogged blood
vessels
(c) Phosphorus-32: is used to detect
the rate of absorption of phosphorus
fertiliser in plants
(d) Carbon-14
Agriculture: to detect the rate of
photosynthesis in plants
Archaeology: to determine the age of
fossils and artifacts
Mind Challenge page 181
5. • Identify the problem: The road is
cracked even though it has been paved
many times
• Clarify the problem:
The soil becomes soft due to the
leakage of underground pipes
• The steps towards solving the
problem:
– Use isotope sodium-24 to detect
leakage of underground pipes.
– After identifying the leakage, dig and
repair the underground pipe leakage.
– After repairing the leakage, make
sure the structure of the soil is
compressed again.
– Repair the surface of the road.
3. Iron is a pure metal, easily oxidised and
forms rust when it reacts with water and
oxygen. Steel is an alloy that makes it
resistant to the reaction with water and
oxygen.
Formative Practice 9.1 page 189
1. Bronze/Brass/Duralumin
2.
Atoms of
foreign
element
Pure metal
Chapter 9
• Pure metal: atoms in the pure metal are
arranged in an orderly manner and in
layers. The layer of atoms in pure metal
easily slides over each other when a
force is applied.
Experiment 9.1 page 186
Questions:
1. Bronze block
2.
Copper
Copper
Tin
Copper
Bronze
3. When the load is dropped or force is
applied on the copper block, the layers of
the copper atoms will slide over on one
another easily resulting in the formation
of a bigger diameter of the dent.
In the bronze block, the presence of tin
atom makes the particles have irregular
arrangement. When the load is dropped
onto the bronze block, the layers of the
copper atoms have difficulty sliding onto
one another and the diameter of the dent
will be smaller.
Experiment 9.2 page 187
Questions:
1. Iron nail
2.
Iron
Iron
Iron
Alloy
Carbon
• Alloy: The difference in size of foreign
atom disrupts the orderly arrangement
of metals. The layer of atoms in alloy is
difficult to slide over each other when
a force is applied. Therefore, alloy is
harder.
3. Duralumin.
Duralumin is strong, light and resistant to
corrosion.
Formative Practice 9.2 page 192
1. Glass: silica
Ceramic: clay
2. Glass:
• to make laboratory apparatus such as
beakers and conical flasks
• to make cooking utensils such as glass
pot, casserole dish
• to make food container such as glass
bottle
Ceramic:
• to make plates and bowls
• to make tiles
• to make flower pots
Steel
Activity 9.3
A Yes.
page 195
13
B Rubber becomes less elastic.
Activity 9.4 page 196
1. Coagulation of latex occurs/White solid is
formed
2. Latex remains in its original condition/
Latex does not coagulate
3. By adding alkali/ammonia into latex
4. Bacterial activity produces acid which can
coagulate latex.
Formative Practice 9.3 page 198
1.
Natural polymer
Monomer
Natural rubber
Isoprene
Starch
Glucose
Synthetic polymer
Monomer
Polythene
Ethene
Polystyrene
Styrene
2.
Natural
rubber
Properties
Vulcanised
rubber
Easily
oxidised
Oxidation
Not easily
oxidised
Soft
Hardness
Hard
Not
resistant
to heat
Heat
resistance
More
resistant to
heat
3. Heating natural rubber with sulphur
• Natural rubber is heated at a
temperature between 100°C to 150°C
at high pressure
• 3% to 5% sulphur is added to the
heated rubber
Summative Practice 9 page 200 – 201
1. (a) Object P: brass
Object Q: bronze
(b) Alloy P: to make door knobs/to
make decorative items/to make food
containers
Alloy Q: to build sculptures/to build
monuments/to make knives
(c) A bronze block is stronger compared
to a copper block due to the presence
14
of foreign atoms in the bronze
block. This will disrupt the orderly
arrangement of the atom in the
bronze block. When force is applied
onto the bronze block, the layers of
atoms have difficulty sliding over one
another thus making it stronger.
(d) Yes, it can.
Because alloy P is hard and resistant
to corrosion making it suitable to be
used. Besides that, alloy P will also
make the body of the ship look better
because alloy P is gold in colour.
2. (a) Borosilicate glass
(b) Borosilicate glass has high resistance
to heat and chemical substances.
(c) Fused silica glass
It has high resistance to heat and is
inert to chemicals.
(d) Yes, it is suitable
It will not break easily when cold or
hot water is placed in it.
3. (a) • Superconductor alloys are used in
the construction of railway tracks
for Maglev train service.
• Magnets are placed at the bottom
of the Maglev train.
• Superconductor alloys are cooled
to a very low temperature and
electric current flows through it to
produce antimagnetic property.
• Maglev train will float a little and the
bottom part of the train will not be in
contact with the railway track.
• This will prevent friction between
the railway track and the Maglev
train.
• Thus, the Maglev train is able to
move at high speed.
(b) MRI machine/Electrical cable/
Microchip
(c) Yes, it can.
• A track needs to be prepared
• Place magnets at the bottom of the
car
• When electricity flows on the track,
the antimagnetic force will be
formed allowing the car to move
without touching the track
• The bottom structure of the car is
specially created to make sure the
car does not derail from the track
No, it cannot
• Cars move without track
• Difficult to place superconductor
alloy on the road to allow electricity
to flow
• The car can crash because there
is no tool to allow the car to be
attached to the runway
Mind Challenge page 201
4. (a) Aim: To study the elasticity of natural
and vulcanised rubber
(b) Hypothesis: When vulcanised rubber
is used, change in the length of the
rubber sheet does not happen.
(c) Variables:
• Manipulated: Type of rubber sheet
• Responding: Change in the length
of rubber
• Constant: Mass of weight/length
and the original thickness of the
rubber
(d) Materials and apparatus: Natural
rubber sheet, vulcanised rubber
sheet, weight 50 g, retort stand and
clamps
(e) Procedure:
1. Record the initial length of the
rubber sheet.
2. Arrange the apparatus and
materials as shown in the figure.
3. Hang a 50 g weight at the bottom
of the natural rubber sheet and
remove it after 1 minute.
4. Observe and record the length of
the rubber sheet.
5. Repeat steps 1 to 4 by replacing
the natural rubber sheet with a
vulcanised rubber sheet.
(f) Setup of apparatus:
Rubber
sheet
Retort
stand
Weight
(g) Tabulation of data:
Type of
rubber
sheet
Initial
Final
Change in
length of length of the length
rubber
rubber of rubber
sheet
sheet sheet (cm)
(cm)
(cm)
Natural
rubber
Vulcanised
rubber
Chapter 10
Formative Practice 10.1 page 211
1. Traditional medicine, modern medicine,
complementary medicine
2. • Analgesic: aspirin/codeine/paracetamol
• Antibiotic: penicillin and streptomycin
• Psychotherapeutic:
− Stimulant: amphetamine
− Antidepressant: imipramine/
amitriptyline
− Antipsychotic: tranquiliser/barbiturate
3. Aloe vera
The gel from the leaves can cool the
sunburnt skin
4. Examples:
Acupuncture/Chiropractic/Traditional
massage/Homeopathy/Herbal therapy
Reasons:
Complementary medicine helps
patients to calm their emotions/relieve
stress/promote wellness and health/
helps to relieve the effect of treatment
or symptoms of treatment such as
chemotherapy.
15
Formative Practice 10.2 page 213
1. Free radicals are atoms or molecules
that lack one electron. Thus, making the
atoms or molecules unstable, reactive
and tend to attack other atoms or other
molecules.
2. Free radicals are formed from the
oxidation process that happens in the
body due to internal and external factors.
3. Internal factors: metabolism/inflammation
External factors: sunlight/factory smoke/
cigarette smoke
Experiment 10.1 page 216
Questions:
1. • In the lime juice
• In the common salt solution
2. Oxidation process happens on the
surface of the apple slices turning the
surface of the apple slices brown.
3. Antioxidant substances such as vitamin C
and common salt
Formative Practice 10.3 page 216
1. Antioxidant are chemical compounds that
can be obtained from chemical synthesis
or natural plants. Antioxidants are needed
by our body to slow down or to stop the
oxidation process.
2. Beta carotene/Lutein/Lycopene/
Vitamin C/Vitamin E
Formative Practice 10.4 page 218
1. Active ingredients are specific
components in a product that have effects
on the cure or prevention of diseases.
2. Intake of unbalanced diet/Lack of
nutrients in food served/For normal
growth and wellness/Improve body
immunity to fight diseases (any two)
Summative Practice 10 page 220 – 222
1. (a) Method M: Complementary medicine
Method N: Modern medicine
16
(b) Follow-up treatment after the cancer
treatment/Weak muscle condition/
Poor blood circulation/Reduce
pressure and stress (any one)
(c) • Analgesic: used to reduce
headaches, migraine and fever
• Antibiotics: used to treat diseases
due to pathogen infections such as
tuberculosis (TB) and syphilis
• Psychotherapeutic: used to treat
mental illness such as depression
and anxiety
(d) Method M can reduce the side
effects of medicine use in method
N. Radiotherapy for example is a
treatment for cancer.
2. (a) Free radicals are formed from
oxidation process that happens in
the body due to internal and external
factors.
(b) External factors such as sunlight,
smoke from factories, cigarette
smoke while internal factors are
metabolism and inflammation
(c) For most individuals, the free radicals
formed naturally due to internal
factors usually are stabilised by
antioxidant substances from the
food intake. For individuals who are
exposed to external factors in excess
such as cigarette smoke, factories
smoke and radiation, many free
radicals will be formed and cannot
be stabilised by the antioxidant
substances from food. This can
cause health problems due to the
presence of additional free radicals in
the body.
3. (a) Antioxidants are chemical
compounds that can be obtained from
chemical synthesis or natural plants.
When antioxidants react with free
radicals, more stable compounds will
be produced, stopping the oxidation
process.
(b) This substance protects body cells
from free radical damage and is
regarded as a defensive line against
diseases.
(c) • Beta carotene is an antioxidant
substance which is commonly
found in most red, yellow or orange
coloured food such as apricots,
carrots, pumpkins, mangoes, sweet
potatoes and peaches.
• Lutein is an antioxidant substance
which is commonly found in large
quantities in green leafy vegetables
such as spinach, cabbage and
broccoli.
• Lycopene is an antioxidant
substance which is commonly
found in papaya, guava,
watermelon, tomato, apricots,
grapefruit and oranges.
• Vitamin C which is also known as
ascorbic acid, is a water-soluble
vitamin. Vitamin C is an antioxidant
substance which is found in citrus
fruits, spinach, broccoli, kiwi,
strawberries, cranberry, cabbage
and green pepper.
4. Massage is a method of manipulating soft
tissues in the body using hands, fingers
and fist. Massage soothes anxiety,
pain, fatigue, muscle tension and nerve
problems.
Mind Challenge page 222
5. (a) Dry and dull skin.
(b) Eating food with less antioxidant
substances.
(c) • Eat fruits and vegetables that have
antioxidant substances.
• Take health products consisting of
antioxidant substances for the skin
• Apply face cream that has
antioxidant substances
6. Busy people need food supplements to
maintain their health. They are also less
involved in recreational activities and
exercise. They eat out because they do
not have time to prepare their own food.
Therefore, they lack nutrients. Intake
of omega-3 protects a person from
heart attack. Vitamin pills complement
unbalanced diet.
7. Health problems she could face:
• Malnutrition due to lack of nutritious
food
• Skin problem causes early aging
because of the lack of antioxidants
• Weak muscle and nerve problems
Solution:
Malnutrition:
• Taking supplement and vitamin pills
that contain various nutrients
Early aging:
• Take supplements or health products
that contain antioxidant substances that
delay the aging process.
Weak muscle and nerve problems:
• Traditional massage once a month to
overcome problems of weak muscle
and nerve.
Chapter 11
Activity 11.2 page 233
1. A pattern of dots in a straight line
is formed./Distance between dots
increases.
2. No. The length of the ticker tapes is
found to be increasing. This is because
the trolley moves with an acceleration/
increasing velocity.
Formative Practice 11.1 page 234
1. (a) Distance: Total length of path
travelled by an object
(b) Displacement: Distance of the
shortest path that connects two
locations in a certain direction.
(c) Velocity: Rate of change of
displacement
17
Formative Practice 11.2
1. Velocity
2. Displacement
3. Velocity (m s–1)
0
t¹
t²
page 239
Time (s)
4. Velocity decreases (gradient of graph
decreases)
Experiment 11.2 page 244
Question:
No, because free fall involves only
gravitational force.
Formative Practice 11.3 page 245
1. (a) gravitational
(b) air
(c) Gravitational acceleration
2. • Before being released, the
displacement of the object is zero. The
object is stationary.
• At the moment the object is released, it
moves with low velocity.
• This can be seen in the small value of
gradient.
• In the final stage when the object is in
free fall, it moves with velocity greater
than at the initial stage.
• This can be seen in the greater value of
gradient.
18
Experiment 11.3 page 248
Questions:
1. The greater the mass of the plasticine,
the longer the oscillation period.
2. The greater the mass of the plasticine,
the greater the inertia of the object.
3. No
Formative Practice 11.4 page 249
1. Inertia is the natural tendency of an
object to resist any change in its original
state, whether being at rest or in motion.
Examples of inertia:
• Dry an umbrella by spinning it fast and
stopping it suddenly.
• The driver is hurled forward when the
brakes are applied suddenly.
2. The greater the mass, the greater the
inertia.
Summative Practice 11 page 251 – 253
1. (a) 24 km + 12 km + 12 km = 48 km
(b) (12 km)2 + (12 km)2
= 16.97 km to the northwest
12 km
12 km
24 km
12 km
16.97 km
12 km
(d) Acceleration: Rate of change of
velocity
2. Displacement = 10 cm
Displacement
Velocity =
Time
10 cm
=
9 ticks × 0.02 s
10 cm
=
0.18 s
= 55.56 cm s–1
(c) 48 km ÷ 2 hours = 24 km h–1
(d) 16.97 km ÷ 2 hours = 8.485 km h–1
2. (a) 8 m + 8 m = 16 m
(b) (8 m)2 + (8 m)2
= 11.31 m to the northeast
(c) 11.31 m ÷ (5 x 60 s) = 0.038 m s–1
3. (a) Gradient of graph
(b) 20 m s–1 ÷ 5 s = 4 m s–2
1
(c)
× (30 s + 15 s) × 20 m s–1 = 450 m
2
4. (a) Graph P because its gradient is
greater compared to Q. Value of
gradient represents the value of
acceleration.
(b) 20 m s–1 ÷ 8 s = 2.5 m s–2
5. (a) 16 cm ÷ 0.2 s = 80 cm s–1
(b) 0 cm s–2/zero. This is because the
velocity of the ticker tape strip is
constant.
6. (a) Inertia is the natural tendency of
an object to resist any change in its
original state, whether being at rest or
in motion.
(b) Both wooden blocks have the same
inertia because their masses are the
same.
(c) Newton’s First Law of Motion states
that an object tends to remain in its
original state, either being at rest or
in motion with uniform velocity if no
external forces acts on it.
7. (a) The motion of an object that is
affected only by gravitational force.
(b) The time taken for the coin to fall is
shorter than the feather in cylinder
tube R, whereas for cylinder tube S,
the time taken for both the coin and
the feather to fall is the same. This
is because cylinder tube R has air,
whereas cylinder tube S is a vacuum.
Cylinder tube R has air resistance.
(c) An object will free fall if no air
resistance acts on it.
Mind Challenge page 253
8. (a) 0.02 s × 10 = 0.2 s
(b) Ticker tape 1:
10 cm ÷ 0.2 s = 50 cm s–1
Ticker tape 5:
50 cm ÷ 0.2 s = 250 cm s–1
(c) The length of each ticker tape strip
will become longer because the
distance between ticks increases.
9. (a) To tighten the head of the hammer
(b) Inertia
(c) • A wet umbrella can be dried by
spinning the umbrella quickly and
stopping it suddenly. Water droplets
will continue to move even when
the umbrella has stopped spinning
due to inertia. So, the water
droplets will fly off the umbrella.
• A driver and passengers of a car
need to wear safety belt to reduce
the effects of inertia.
Chapter 12
Formative Practice 12.1 page 257
1. United States of America, Russia,
France, Japan
(any three)
2. • Produce a lot of energy compared to
fossil fuels
• Release very little greenhouse gases
compared to other sources
Formative Practice 12.2 page 263
1. (a) nuclear fission, slow neutron, splits,
energy
(b) temperature
Formative Practice 12.3 page 266
1. • World will be destroyed
• Number of cancer cases increases
• War will break out among countries
with nuclear weapons.
2. To ensure whether nuclear weapons can
function.
Formative Practice 12.4 page 267
1. Natural gas, hydro
2. • Fossil fuels will deplete
• Nuclear energy releases very little
greenhouse gases
• The rate of production of energy by
nuclear energy sources is greater
compared to fossil fuels
Summative Practice 12 page 269 – 270
1. (a) France, Slovakia
(b) • France uses nuclear energy to
generate electricity to a large part
of the country.
19
• Slovakia generates income by
supplying electricity generated from
power stations to neighbouring
countries.
(c) • Can produce huge amounts of
energy compared to other energy
sources
• Release very little greenhouse
gases compared to other energy
sources
• Low maintenance cost indirectly
strengthens national economy
(any two)
2. (a) Nuclear fission
(b) Nuclear fission occurs when a
low-velocity neutron bombards
a heavy radioactive nucleus and
causes the nucleus to split into
two lighter and more stable nuclei
together with the release of a lot of
energy.
(c) The rate of nuclear reaction would be
too high and can cause explosion.
3. (a) Nuclear fusion
20
(b) The Sun has very high temperature/
Rich in hydrogen
(c) Earth would not receive sunlight and
heat anymore. All living things cannot
survive.
4. (a) Nuclear fission
(b) To produce a lot of heat
(c) • It has 2 m-thick walls that are made
of concrete and lead
• Has boron control rods that absorb
excess neutrons so that reaction is
under control
(d) Leakage of radioactive radiation
occurs.
Mind Challenge page 270
5. • Nuclear energy can be converted into
electricity using the nuclear reactor.
• The nuclear energy released in the
form of heat energy, is used to heat
water and produce steam.
• The steam produced is used to spin
turbines and generate electricity.