Question 1

The graph below shows the average size of the opening of stomata found on the leaves of green plants over a period of 12 hours. Which of the following is the main reason for the change in the size of the opening between 6 a.m. and 6 p.m?

Accepted Answer

C. To allow the leaves to take in more carbon dioxide.. Stomata open widest during the day (peaking around noon) when photosynthesis is most active. Their main function is to allow carbon dioxide, a raw material for photosynthesis, to enter the leaf. During daylight hours the plant needs more carbon dioxide, so the stomata open wider.

Question 2

The graph below shows the rate of photosynthesis for trees A, B and C, which had been grown at an open space in the same habitat and exposed to similar conditions. The diagram below shows the size and position of each of the trees within their habitat. Which of the following correctly matches the trees X, Y and Z to the rate of photosynthesis shown in the graph above?

Accepted Answer

C. A=Y, B=Z, C=X. Rate of photosynthesis depends on the amount of leaves/size of the tree exposed to sunlight. From the bar graph, A has the highest rate, C is second, and B the lowest. Tree Y is the largest (most leaves, highest rate = A), tree X is medium (= C), and tree Z is the smallest (lowest rate = B). This matches A=Y, B=Z, C=X.

Question 3

Michael covered different parts of a leaf with different materials as shown in the diagram below. The plant was left in the open for two days before Michael tested the leaf for the presence of starch using some iodine solution. Which of the following correctly shows the most likely colour of iodine solution on the leaf?

Accepted Answer

C. A=turned dark blue, B=turned dark blue, C=turned dark blue, D=remained yellowish brown, E=turned dark blue. Iodine turns dark blue where starch is present. Starch forms only in parts that received light. Regions A, B, C and E were exposed to light (uncovered or covered with clear/transparent plastic which lets light through) so they photosynthesise, make starch and turn dark blue. Region D was covered with aluminium foil which blocks light, so no starch forms and it remains yellowish brown.

Question 4

Which of the following habitats are suitable for earthworms to live in? A leaf litter, B garden, C desert

Accepted Answer

B. A and B only. Earthworms need moist, cool, soil-rich habitats. Leaf litter (A) and garden soil (B) are damp and provide moisture and organic matter. A desert (C) is too dry and hot for earthworms to survive. Therefore only A and B are suitable.

Question 5

The diagram below shows a food web in a grassland community. The following graph shows a change in the population size of antelopes in the community. Which two of the following events could have caused the change between points P and Q? A There was a decrease in the amount of rain. B There was a decrease in the population of zebras. C There was an increase in the population of plants. D There was an increase in the population of cheetahs.

Accepted Answer

B. A and D. Between P and Q the antelope population fell. A decrease in rain (A) reduces plant growth, so antelopes have less food and their population drops. An increase in cheetahs (D) means more predators eat antelopes, also reducing the population. Both A and D cause a decrease, so the answer is A and D.

Question 6

Which of the following statements about a pond habitat and a single tree habitat are true? A The plants in both habitats need sunlight to survive. B An organism taken from the single tree can live inside the pond. C The organisms in the pond need more water than those in the single tree. D There is more oxygen available in the pond as compared to the single tree.

Accepted Answer

A. A and C only. Statement A is true: all plants, whether in a pond or on a tree, need sunlight to make food. Statement C is true: aquatic (pond) organisms depend on water and need more water than land organisms living on a tree. Statement B is false because a tree organism is not adapted to live underwater, and D is false because there is generally more oxygen available in air (around a tree) than dissolved in pond water. So A and C only.

Question 7

Study the food chain below: A → B → C → D. Based on the food chain, which one of the following organisms correctly represents organism A, B, C and D?

Accepted Answer

B. A=grass, B=rabbit, C=snake, D=eagle. A food chain must start with a producer and go from prey to predator. Grass (producer) → rabbit (eats grass) → snake (eats rabbit) → eagle (eats snake) is a valid chain. This matches option B.

Question 8

The following statements on food chains were made by some pupils. Which pupil had made an incorrect statement? Peter: A food chain consists only of food consumers. Ailing: A food chain shows predator-prey relationship. Rizar: A food chain must always end with the last consumer. Devi: A food chain must always begin with a food producer.

Accepted Answer

A. Peter. Every food chain begins with a food producer (a green plant), not only consumers. Peter's statement that a food chain consists only of consumers is therefore incorrect.

Question 9

Study the food web below. Which one of the following statements can be concluded based on the food web?

Accepted Answer

D. S is a prey of T but a predator of Q.. In the food web, arrows point from prey to predator. S is eaten by T (so S is prey of T) and S eats/points to organisms it preys on including Q's relationship — S is a predator of Q. The relationship 'S is a prey of T but a predator of Q' is consistent with the web, making D the correct conclusion.

Question 10

Serene placed a slice of moist bread inside a transparent plastic bag as shown below. After 1 week, she made the following observations: The bread had shrunk in size. The bread had become very soggy. The bread was covered with green mould. Which one of the following can be concluded based on her observations?

Accepted Answer

D. Bread mould breaks down the bread and releases water.. The bread shrinking shows the mould broke down/decomposed the bread. The bread becoming soggy (wetter) shows water was released during this breakdown. Together these observations lead to the conclusion that bread mould breaks down the bread and releases water.

Question 11

Jonathan had a discussion with his classmates on ways to conserve water. The following suggestions were made: A Fixing a leaking pipe. B Turning off the shower when soaping. C Using a basin of water to wash kitchen utensils. D Decreasing the time between one car wash session to the next car wash session. Which of the above suggestions would help to conserve water?

Accepted Answer

C. A, B and C only. Fixing a leaking pipe (A), turning off the shower when soaping (B) and using a basin to wash utensils (C) all reduce water used and conserve water. Decreasing the time between car washes (D) means washing the car more often, which uses more water, so it does not conserve water. Answer: A, B and C only.

Question 12

Two identical towels soaked with an equal amount of water were spread out on identical trays. They were exposed to different conditions as shown below. Towel A: Temperature of surrounding 32°C, Wind Present. Towel B: Temperature of surrounding 25°C, Wind Not present. If the conditions of the surrounding remain constant, which of the following graphs correctly shows the rate of evaporation of water for each towel over a period of two hours?

Accepted Answer

A. Graph 1: two constant horizontal lines, A higher than B. Towel A is in higher temperature (32°C) with wind present, so its water evaporates faster than Towel B (25°C, no wind). Because the surrounding conditions remain constant, each rate stays steady (a horizontal line) over time. The rate for A must be higher than B, which matches graph 1.

Question 13

The diagram below shows the stages of growth of a flowering plant. Which one of the following correctly identifies processes A, B, C and D?

Accepted Answer

C. Seed dispersal=D, Germination=A, Becoming an adult plant=B, Pollination and fertilisation=C. Following the life cycle: D is seed dispersal (seeds leaving the pods), A is germination (seed growing into a seedling), B is the seedling becoming an adult plant, and C is pollination and fertilisation (adult flowering plant producing new seeds). This matches option C.

Question 14

Mei Mei conducted an experiment with flower P on a plant. She removed some parts of the flower. Then, she transferred pollen to the remaining parts of flower P. The flower no longer becomes a fruit after that. Mei Mei then conducted another experiment with flower Q on the same plant. She removed some parts of flower Q. Then, she transferred pollen to the remaining parts of flower Q. After some time, flower Q formed a fruit. Which one of the following correctly shows the parts that had most likely been removed from flowers P and Q?

Accepted Answer

A. Flower P=stigma, Flower Q=anther. A fruit forms only if pollen reaches the stigma and fertilisation occurs in the ovary. Flower P did NOT form a fruit despite pollen being added, so the stigma (needed to receive pollen) must have been removed. Flower Q DID form a fruit, so the removed part was not essential to fruit formation — removing the anther (which only produces pollen) still allows fruit formation since pollen was supplied. Answer: P=stigma, Q=anther.

Question 15

Ahmad had to classify the seeds of three different flowering plants (coconut, love grass, balsam). He classified them with the help of the chart below. Which of the following correctly represent questions A and B?

Accepted Answer

D. Question A: Is a fibrous husk present?, Question B: Are hooks present?. The coconut has a thick fibrous husk (for water dispersal), so 'Yes' to Question A (Is a fibrous husk present?) identifies coconut. Love grass seeds have tiny hooks (for animal dispersal), so 'Yes' to Question B (Are hooks present?) identifies love grass. Balsam remains ('No' to both). Answer: A = fibrous husk present, B = hooks present.

Question 16

The diagram below shows the air sacs of the lungs of a smoker and a non-smoker. Cigarettes contain a substance known as tar which blocks the walls of the air sacs and prevents substances from passing through it. Based on the information above, which of the following statements are true? A The air sacs of smokers will allow less oxygen to enter the bloodstream. B The oxygen that enters the bloodstream of smokers will be mixed with tar. C Blood flowing in the blood vessels of a smoker is mixed with tar. D To get the same amount of oxygen as a non-smoker, the smoker will have to breathe faster.

Accepted Answer

A. A and D only. Tar blocks the air-sac walls, so less oxygen can pass into the bloodstream (A true). To make up for less oxygen per breath, the smoker must breathe faster (D true). Tar blocks substances from passing through, so it does NOT enter the blood — statements B and C are false. Answer: A and D only.

Question 17

A few passengers were trapped in a lift. The fan in the lift was not working and the lift was tightly shut. Which one of the following correctly shows the change in the amount of air, oxygen and carbon dioxide in the lift when the passengers were trapped for 2 hours?

Accepted Answer

D. amount of air=unchanged, carbon dioxide=increased, oxygen=decreased. The lift is sealed so the total amount of air stays unchanged. As passengers breathe, they take in oxygen (oxygen decreases) and breathe out carbon dioxide (carbon dioxide increases). Answer: air unchanged, carbon dioxide increased, oxygen decreased.

Question 18

The diagram below shows a cactus plant. This desert plant has white, needle-like leaves to help it reduce water loss. Which of the following is not found in the leaf cells of the cactus plant?

Accepted Answer

C. chloroplast. The cactus's needle-like leaves are white, not green, meaning they contain no chlorophyll. Chloroplasts (which contain chlorophyll) would therefore not be found in these leaf cells; photosynthesis occurs in the green stem instead. Cell wall, nucleus and cell membrane are found in all plant cells.

Question 19

Study the diagram below which shows parts of the digestive system. Which one of the following has been correctly matched to its function?

Accepted Answer

D. absorption of digested food=R, absorption of water=Q. In the diagram, P is the stomach, Q is the large intestine, and R is the small intestine. The small intestine (R) absorbs digested food; the large intestine (Q) absorbs water. Answer: digested food = R, water = Q.

Question 20

Study the chart below. Which one of the following correctly identifies Q, R, S and T?

Accepted Answer

A. Q=toadstool, R=fern, S=spider lily, T=sunflower. Q = 'No' to making its own food → a non-green organism (toadstool/fungus). R = makes food but 'No' to producing seeds → a spore-producing plant (fern). S = produces seeds but 'No' to brightly-coloured flowers → spider lily (dull/greenish flower — actually wind/less showy). T = 'Yes' to brightly-coloured flowers → sunflower. This matches option A: Q=toadstool, R=fern, S=spider lily, T=sunflower.

Question 21

Which one of the following shows the correct energy conversion when a television is switched on?

Accepted Answer

C. Electrical Energy → Sound Energy + Light Energy + Heat Energy. A television runs on electrical energy. When switched on it produces sound (from speakers), light (from the screen) and heat (as a by-product). So electrical energy → sound + light + heat energy, which is option C.

Question 22

Sam was playing badminton with his brother. They hit the shuttlecock between each other. Which of the following is true when the shuttlecock moved from point B to point A?

Accepted Answer

B. The amount of gravitational potential energy of the shuttlecock is more at point A than at point B.. Point A is at the top of the net (higher) and point B is lower (near the racket). Gravitational potential energy increases with height. As the shuttlecock moves from the lower point B to the higher point A, it gains height, so it has more gravitational potential energy at A than at B.

Question 23

A fruit dropped from a tall tree with a loud "thud" and then rolled away on the ground. Which of the following statements correctly states the energy changes that had taken place?

Accepted Answer

C. Some of the gravitational potential energy in the fruit had been converted into sound energy and kinetic energy.. As the fruit falls, its gravitational potential energy (from its height on the tree) is converted to kinetic energy as it moves and to sound energy (the loud 'thud') when it hits the ground and rolls away. Answer: gravitational potential energy → sound energy and kinetic energy.

Question 24

The diagram below shows different energy conversions. Which one of the following devices shows both energy conversions A and C when it is in use?

Accepted Answer

D. a solar-powered toy car. From the diagram, A = light energy → electrical energy, and C = electrical energy → kinetic energy. A solar-powered toy car converts light energy from the sun into electrical energy (A) and then electrical energy into kinetic energy to move the car (C). Answer: a solar-powered toy car.

Question 25

Marcus conducted an experiment as shown in the diagram below. The wooden block is not attached to the spring. Marcus pushed the wooden block against the spring until it is fully compressed before releasing the wooden block. He then measured the distance travelled by the wooden block along the ramp. He repeated the experiment several times and found that the wooden block could only travel a maximum distance of 13 cm away from the spring. Which of the following changes would enable the wooden block to travel a longer distance? A Use a longer spring of the same elasticity. B Apply lubricant to the surface of the ramp. C Use a spring that is more easily compressed.

Accepted Answer

B. A and B only. A longer spring of the same elasticity stores more elastic potential energy when compressed, pushing the block further (A helps). Applying lubricant reduces friction on the ramp, so less energy is lost and the block travels further (B helps). A spring that is more easily compressed stores less energy, so it would push the block a shorter distance (C does not help). Answer: A and B only.

Question 26

The diagram below shows a toy known as "spring rainbow". By pulling one end of the spring towards position 1, the toy would start moving downwards continuously on its own until it reaches position 5. Which of the following forces are acting on the toy as it moves towards position 5? A Frictional force, B Magnetic force, C Gravitational force, D Elastic spring force

Accepted Answer

C. A, C and D only. As the spring toy 'walks' down the steps: gravitational force (C) pulls it down; the elastic spring force (D) of the coiling/uncoiling spring drives its motion; and frictional force (A) acts between the spring and the steps. There is no magnetic force (B) involved. Answer: A, C and D only.

Question 27

Sining shone a laser pointer at a mirror as shown in the diagrams below. Which diagram correctly shows the path of a ray of light from the laser pointer?

Accepted Answer

B. Diagram 2. Light travels in a straight line and reflects off a mirror so that the angle of incidence equals the angle of reflection. The ray must leave the laser pointer, hit the mirror and reflect off at an equal angle, with the arrows pointing in the correct direction of travel (from pointer to mirror to eye/target). Diagram 2 shows this correct path with the reflected ray at an equal angle and correct arrow directions.

Question 28

Zachary wanted to investigate which material was best at reflecting light. He set up his experiment in a dark room as shown below. Zachary shone a lighted torch onto the wall and walked towards it. When he could clearly see material P hung on the wall, he stopped and measured the distance x. He repeated the experiment with materials Q, R and S each time. His results were shown below. Material P: x=190 cm, Q: x=330 cm, R: x=250 cm, S: x=280 cm. Based on Zachary's results, which is the best material to be used to make a safety vest for cyclists to wear at night?

Accepted Answer

B. Q. The material that can be seen clearly from the greatest distance reflects light best. Material Q was visible from the largest distance (x = 330 cm), meaning it reflects light most effectively, making it the best material for a cyclist's safety vest so it can be seen from far away at night.

Question 29

Liam set up the experiment as shown below. Container X held 400ml water and Container Y held 200ml water, each with a balloon over the top and heated by a candle flame. He noticed that the balloons on both set-ups took the same amount of time to be inflated to the same size. Which of the following are possible reasons for Liam's observation? A Water in Container X is cooler than Container Y. B Container X conducts heat better than Container Y. C Container X is heated by a stronger flame than container Y.

Accepted Answer

C. B and C only. Container X has more water (400 ml) than Y (200 ml), so normally X would need more time to heat up and inflate its balloon. For both balloons to inflate in the same time, X must gain heat faster. This can happen if Container X conducts heat better (B) or is heated by a stronger flame (C). Statement A (X being cooler) would slow X down, not help. Answer: B and C only.

Question 30

The diagram below shows a lamp placed at the same distance from two identical glass containers A and B. Container A is covered with a piece of woollen material while container B is covered with a clear plastic sheet. The temperature measured in both containers are recorded as shown in graphs below. Which one of the following statements correctly explains the results as shown in the graph?

Accepted Answer

A. More heat is trapped in container B as plastic is a poorer conductor of heat than wool.. The graph shows Container B (clear plastic) heats up more/faster than Container A (wool). The clear plastic lets light from the lamp pass through and warm the container, and being a poorer conductor of heat it traps more heat inside, so B's temperature rises higher. Answer: more heat is trapped in container B as plastic is a poorer conductor of heat than wool.

P6 Science SA1 2014 — Nanyang

Related Sparks

Related reads

P6 Science SA1 2014 — Nanyang

Related papers

Related Sparks

Related reads