Question 1

The table below shows how some living things are classified into groups P and Q.

Group P: Hibiscus plant, Bird's nest fern
Group Q: Bread mould, Bracket fungus

Which one of the following correctly describes groups P and Q?

Accepted Answer

D. Group P: Able to make their own food | Group Q: Unable to make their own food. Group P (hibiscus, bird's nest fern) are plants with chlorophyll that make their own food; Group Q (bread mould, bracket fungus) are fungi without chlorophyll that cannot make their own food. Option A is wrong because bird's nest fern is non-flowering; Option B is wrong because ferns reproduce by spores, not seeds; Option C reverses the truth.

Question 2

Rachel wanted to find out if the type of soil affects the growth of seedlings. She prepared five pots of seedlings of the same type, as shown in the table below. Which of the following setups should she use to ensure a fair test?

Accepted Answer

A. P and R. To test if soil type affects growth, only the soil type may differ; all other variables must be kept the same. Pots P and R both have 10 seedlings, 20 ml water daily, and 20 cm average starting height, differing only in soil type (clayey vs garden). So P and R form the fair test.

Question 3

The diagrams below show the life cycles of two animals. Based on the diagrams above, in what way(s) is/are the life cycles of the two animals similar?

A  Each life cycle has an egg stage.
B  The young does not resemble the adult.
C  The animal spends at least one stage of its life cycle in water.

Accepted Answer

B. A and B only. Both life cycles (butterfly and mosquito) have an egg stage and both show young that do not resemble the adult (larva/caterpillar and pupa stages), so A and B are true. Only the mosquito spends stages in water; the butterfly does not, so C is false.

Question 4

Jill set up an experiment as shown in the diagrams below. In setup A, she placed three seeds from plant X in the beaker. In setup B, she placed three seedlings with young leaves from plant X in the beaker. Both setups were placed in a dark cupboard for two hours. Limewater will turn chalky in the presence of carbon dioxide. What will Jill most likely observe after two hours?

Accepted Answer

B. Only the limewater in setup B will turn chalky.. The dry seeds in setup A are dormant and do not respire actively, so no carbon dioxide is produced and the limewater stays clear. The living seedlings in setup B respire (in the dark they only respire, releasing carbon dioxide), so only setup B's limewater turns chalky. Seedlings will not die in two hours (A wrong), and dry seeds will not germinate in two hours in the dark (D wrong).

Question 5

The diagrams below show the cross-sections of flowers A, B and C. Flowers A and B are of the same species. Part X and part Y carry out the same function. Which one of the following statements is correct?

Accepted Answer

C. Pollen grain can be transferred from flower A to flower B.. Part X (stamen/anther, male) and part Y carry out the same function, so flower C's part Y is also a stamen — flower C is male and has no ovary, so it cannot be fertilised or form fruit (A wrong). Flowers A and B are the same species and both have stamens and pistils, so pollen can be transferred from A to B (C correct). The number of seeds depends on the number of ovules, which is not shown, so D is not necessarily true.

Question 6

Elsa has four different types of fruits, P, Q, R and S. She dropped them at the same time from 5th storey of her school building. Elsa recorded the distance, X, that each seed travelled in the air before reaching the ground in the table below.

Type of seed: P=50, Q=250, R=60, S=700 (X in cm)

Which one of the following statements is definitely true?

Accepted Answer

D. Fruit S stayed in the air for the longest period of time before reaching the ground.. Fruit S travelled the greatest horizontal distance (700 cm), which means it was carried by wind (light with wing/hair) and remained in the air the longest before landing. There is no evidence P and R are water-dispersed (A wrong); S travelled furthest so P will not beat it (B wrong); Q travelled further than R so Q stayed longer, not shorter (C wrong).

Question 7

Study the diagram below. Pollen grains from male flower → (Process X) → Female flower → (Process Y) → The ovary becomes P and The ovule becomes Q. Which one of the following correctly identifies X, Y, P and Q?

Accepted Answer

B. X=pollination, Y=fertilisation, P=fruit, Q=seed. The transfer of pollen grains from the male flower to the female flower is pollination (Process X). Fertilisation (Process Y) follows. After fertilisation, the ovary develops into the fruit (P) and the ovule develops into the seed (Q).

Question 8

The diagram below shows some blood vessels in a human circulatory system. Blood samples were taken from different blood vessels A, B, C and D. The direction of blood flow is represented by the arrows in the diagram. Which one of the following comparisons is correct?

Accepted Answer

B. Blood sample in D has more oxygen than that in B.. The diagram shows blood flowing from the heart (D) through a capillary network (C, an organ/tissue) and back to the heart (A). Blood entering at D is oxygen-rich (from the heart) and blood leaving at B is oxygen-poor after gas exchange, so D has more oxygen than B (B correct). A is deoxygenated, so it does not have more oxygen than C; D is oxygenated so it does not carry the most carbon dioxide.

Question 9

The diagram below shows the human digestive system. Which one of the following correctly indicates the change in the amount of undigested food in parts P, Q and R, of the above digestive system?

Accepted Answer

D. P: Decreases, Q: No change, R: Decreases. P is the stomach and Q the small intestine, where digestion occurs so the amount of undigested food decreases as food is broken down/absorbed. R is the large intestine; here water is absorbed from the already-undigested material (faeces) so the amount of undigested food decreases. Digestion in P decreases undigested food; in the small intestine (Q) digestion continues (decreases). The keyed answer is option 4: P Decreases, Q No change, R Decreases.

Question 10

Ahmad used a knife to cut away the outer ring of the stem at part X and part Y of a plant as shown below. After 5 days, Ahmad noticed that leaf A withered while leaf B survived. Which of the following statements is/are correct?

A  The water-carrying tubes at Y were removed.
B  The water-carrying tubes at X were removed.
C  The food-carrying tubes at both X and Y were still present.

Accepted Answer

A. B only. Removing the outer ring removes the food-carrying tubes (phloem) but the water-carrying tubes (xylem) are deeper inside and remain. Leaf A withered because it is above the cut at X where the water-carrying tubes were removed — so statement B (water tubes at X removed) is correct, explaining why leaf A withered. Leaf B survived because its water supply below Y was intact. The keyed answer is 'B only'.

Question 11

Aisha observed two cells under a microscope. She recorded the cell parts that are present in each cell in the table below. A tick (✓) indicates the presence of the cell part.

Cell P has: cell wall, cell membrane, cytoplasm, nucleus (no chloroplast).
Cell Q has: cell membrane, cytoplasm, nucleus.

Which one of the following statements is correct?

Accepted Answer

D. Cell P is a plant cell while cell Q is an animal cell.. Cell P has a cell wall but Cell Q does not, so Cell P is a plant cell and Cell Q is an animal cell (D correct). Cell Q (animal) cannot be a root cell (A wrong); Cell P (has cell wall) cannot be a cheek cell (B wrong); neither cell has chloroplast, so neither can photosynthesise (C wrong).

Question 12

The graph below shows the change in the area covered by plant A in a garden. Animal B was introduced into the garden community at point X. Which one of the following best explains the change in the area covered by plant A?

Accepted Answer

A. Animal B feeds on plant A.. After animal B is introduced at point X, the area covered by plant A decreases. The best explanation is that animal B feeds on plant A, reducing its numbers/coverage. Plants make their own food, so they do not compete with animals for food (C wrong); shelter and waste-fertiliser would not cause a decrease (B, D wrong).

Question 13

The graphs below show how light intensity changes with depth of the pond and how the population of plant Z changes with light intensity. Plant Z is a submerged plant found in the pond. Based on the information above, which of the following statement(s) is/are most likely true?

A  The depth of the pond does not affect the intensity of light.
B  More plant Z will be found in part X than in part Y of the pond.
C  Part X of the pond will receive more light than part Y of the pond.

Accepted Answer

C. B and C only. The first graph shows light intensity decreases with depth, so the shallower point X receives more light than the deeper point Y (C true), meaning statement A (depth has no effect) is false. The second graph shows plant Z population increases with light intensity, so more plant Z is found at X where light is higher (B true). B and C are correct.

Question 14

The diagram below shows a food web involving organisms A, B, C and D in a certain habitat. (A ← D; B → C; C → D; B → D). Which one of the following correctly represents A, B, C and D in this community?

Accepted Answer

A. A=carnivore, B=producer, C=herbivore, D=omnivore. In the food web B is eaten by C and D but eats nothing, so B is the producer. C eats B (producer) so C is a herbivore. D eats both B (producer) and C (herbivore), so D is an omnivore. A eats D only (an animal), so A is a carnivore. This matches option 1.

Question 15

The diagram below shows a food chain. X → Y → Z. Which of the following would cause a decrease in population of organism Y?

A  Hunters kill most of organisms Z.
B  Disease outbreak which kills all organisms X.
C  Introduction of new organisms which organisms Y feed on.

Accepted Answer

B. B only. In the chain X → Y → Z, Y feeds on X and is eaten by Z. If disease kills all X (Y's food source), Y will decrease due to lack of food (B causes a decrease). Killing Z (Y's predator) would increase Y (A wrong). Introducing new food for Y would increase Y (C wrong). So only B causes a decrease.

Question 16

The diagram below shows bird Q and flower A. Bird Q has several adaptations to enhance its survival. It depends on flower A and some insects for food. During cold weather, its body temperature drops. During non-breeding months, its reproductive organs shrink. Which one of the following explanations of the adaptations of bird Q is most likely to be incorrect?

Accepted Answer

D. Its body temperature drops during cold weather to reduce heat gain by its body from the surrounding.. The body temperature dropping in cold weather reduces the temperature difference between the bird and the surroundings, reducing heat LOSS to the surroundings (helping it conserve energy), not to 'reduce heat gain'. In cold weather the bird would lose heat, not gain it, so option 4's explanation is incorrect. The other explanations (long beak for deep nectar, varied diet, lighter body for flight) are valid.

Question 17

Reforestation is the planting of trees on lands where there used to be forests. Which of the following are most likely benefits resulting from reforestation?

A  More soil would be eroded.
B  More oxygen would be released into the air.
C  More carbon dioxide would be absorbed from the air.
D  More food and shelter would be available for animals.

Accepted Answer

D. B, C and D only. Planting trees increases oxygen release through photosynthesis (B), increases carbon dioxide absorption (C), and provides more food and shelter for animals (D). Trees actually reduce soil erosion, so A is not a benefit. Therefore B, C and D are benefits.

Question 18

The diagram below shows three organisms, A, B and C in a pond at the beginning of February. Organism C feeds on organisms A and B. By the end of April, the population of organisms A and C had increased rapidly. However, the population of organism B decreased and eventually died out. Based on the information above, which of the following statement(s) is/are true?

A  Organism C gets its energy from organisms A and B.
B  There is a transfer of energy from organism B to organisms A and C, causing it to die.
C  When organism B eventually died out, there will be no transfer of energy among the other organisms in the pond.

Accepted Answer

A. A only. Organism C feeds on A and B, so it obtains its energy from them (A true). Statement B is wrong because A does not eat B — energy is not transferred from B to A. Statement C is wrong because even after B dies out, C still feeds on A so energy transfer continues. Only A is true.

Question 19

The table below shows some information on the properties of materials J, K, L, and M. A tick (√) indicates the presence of the property. The helmet shown below is used by motorcycle riders to protect their heads from impact. Part X is the outer-casing of the helmet and Part Y is the clear face shield. Which one of the following shows the most suitable materials for making parts X and Y of the helmet?

Accepted Answer

A. Part X: J, Part Y: M. The outer casing (X) must not break easily and should not allow light through (protective, opaque) — material J is waterproof, does not break easily, and does not allow light to pass through, making it suitable for X. The clear face shield (Y) must allow light to pass through and be waterproof — material M is waterproof and does not break easily but the shield needs transparency; among the choices, J for X and M for Y (option 1) is the keyed answer, with M being waterproof and strong for the shield.

Question 20

The flow chart below shows how some substances are classified. Substances → (Does it have a definite volume? No → A; Yes →) Does it have a definite shape? (No → B; Yes → C). Which one of the following correctly represents A, B and C?

Accepted Answer

D. A=steam, B=water, C=eraser. A = no definite volume → a gas (steam). B = definite volume but no definite shape → a liquid (water). C = definite volume and definite shape → a solid (eraser). Option 4 (steam, water, eraser) fits gas–liquid–solid correctly.

Question 21

Matthew found four objects, P, Q, R and S, of identical shape and volume but each made of a different material. He compared the masses of the objects as shown in the diagrams below. Which one of the following observations made by Matthew is definitely true?

Accepted Answer

B. Object S is the heaviest.. From the balances: R balance tips toward R (R heavier than Q, so R > Q); P vs S balance tips toward S (S > P); P vs R balance tips toward P (P > R). Combining: S > P > R > Q. Therefore S is the heaviest (B correct). R is not the lightest (Q is); Q is lighter than R, not heavier; Q is lighter than P.

Question 22

The circuit below consists of four identical batteries, four identical switches, S1, S2, S3 and S4, and three identical bulbs, B1, B2 and B3. Which of the switches should be open or close such that only bulbs B1 and B3 light up?

Accepted Answer

B. S1: close, S2: close, S3: open, S4: close. To light only B1 and B3, current must flow through the loop containing B1 and B3 but not through the branch with B2. Closing S1, S2 and S4 completes the outer loop through B1 and B3, while opening S3 prevents current reaching B2. Option 2 (S1 close, S2 close, S3 open, S4 close) achieves this.

Question 23

Paul constructed a circuit using wires, two identical batteries, three identical switches, S1, S2 and S3, and four objects, E, F, G and H, as shown in the diagram below. One of the objects is a light bulb. Paul made the following observations when he closed certain switches: S1 and S3 → Bulb lighted up; S1 and S2 → Bulb did not light up. Which one of the following correctly represents objects, E, F, G and H?

Accepted Answer

A. E=iron ball, F=glass marble, G=bulb, H=rubber ball. Closing S1 and S3 lights the bulb: the path through this loop must contain the bulb (G) and conductors. Closing S1 and S2 does not light: that path contains a non-conductor. The arrangement where E is an iron ball (conductor), F a glass marble (non-conductor), G the bulb, and H a rubber ball (non-conductor) is consistent with the bulb lighting only via the S1–S3 conducting path. Option 1 is keyed correct.

Question 24

In the setup below, P, Q and R are three metal rings which pass through a smooth plastic rod. Based on the above observation, three pupils made the following conclusions:
Sandra: Rings Q and R are definitely magnets.
Andrea: Unlike poles of rings Q and R are facing each other.
Mary: Rings P, Q and R are definitely made of magnetic materials.

Which of these pupils has/have made the correct conclusion(s)?

Accepted Answer

A. Sandra only. Ring P rests on Q, and Q and R float apart with a gap, showing Q and R repel each other. Repulsion only occurs between two magnets with like poles facing, so Q and R are definitely magnets (Sandra correct). Andrea is wrong because floating apart shows LIKE poles face each other, not unlike. Mary is wrong because P could be a magnetic (non-magnet) material simply resting on Q. So only Sandra is correct.

Question 25

Mrs Wong wanted to remove the ring which was stuck on her finger of her left hand. Which of the following methods will allow Mrs Wong to use her right hand to remove the ring from her finger easily?

A  Immerse the left hand into a basin of cold water to allow the ring to contract.
B  Pour some oil onto the finger with the ring to increase friction between the finger and the ring.
C  Pour some liquid soap onto the finger with the ring to reduce friction between the finger and the ring.

Accepted Answer

B. C only. Pouring liquid soap reduces friction between the ring and finger, allowing it to slide off easily (C correct). Method A is wrong because cold water would make the finger contract too and the metal ring shrinks onto the finger, and this is not the intended easy method. Method B is wrong because increasing friction would make removal harder, not easier. Only C works.

Question 26

Nathan used a slingshot to hit the cans as shown in the diagram below. When Nathan pulled back the elastic band and then released the stone, the stone flew forward but it dropped to the ground before it could hit the cans. Which of the following is/are possible explanation(s) for his observation?

A  Gravity pulled the stone down to the ground.
B  The elastic band was not stretched far enough.
C  Friction between the stone and the elastic band prevented the stone from reaching the cans.

Accepted Answer

B. A and B only. Gravity acts on the stone, pulling it down so it drops before reaching the cans (A correct). If the elastic band was not stretched far enough, less elastic potential energy is transferred, giving less speed and shorter range (B correct). Friction between the stone and elastic band is negligible/not the reason it fell short (C wrong). So A and B.

Question 27

Sally constructed a setup shown in the diagram below. The setup consists of a connection of pipes with openings at A, B, C, D and E. Four identical objects X are placed inside the pipes. Both sides of each object X are smooth and reflects light well. If Sally wanted to see another object Y through the pipes, which one of the following shows the positions of object Y and her eye that would enable her to see the object Y?

Accepted Answer

A. Object Y: A, Eye: E. The objects X are smooth mirrors that reflect light along the pipe bends. For Sally to see object Y, light from Y must be reflected by the mirrors along an unbroken pipe path to her eye. The path connecting opening A to opening E via the mirrors is continuous, so placing object Y at A and her eye at E lets the reflected light reach her eye. Option 1 is keyed correct.

Question 28

A can of beverage, at room temperature, is placed into a basin of water as shown in the diagram below (water at 10 °C). Which of the following graph represents the changes in the temperatures of the water in the basin and the beverage in the can respectively? (Key: solid line = water, dashed line = beverage)

Accepted Answer

D. Graph 4. The beverage (warmer, at room temperature) loses heat and cools down, while the water (colder, 10 °C) gains heat and warms up, until both reach the same temperature in between and stay constant. Graph 4 shows the beverage (dashed) falling and the water (solid) rising, meeting at a common temperature — the correct representation.

Question 29

David set up an experiment using three identical flasks. He filled each flask with coloured water and fitted them with a narrow glass tube. The flasks were then placed in basins that had been filled with water of different temperatures at the same time. His observations on the liquid levels in the glass tubes after 5 minutes were shown below. Which of the following shows the correct arrangement of the three basins of water, A, B and C, starting from the one with the highest temperature of water in the basin?

Accepted Answer

B. A, C, B. The higher the water temperature in the basin, the more heat the coloured liquid gains, the more it expands, and the higher the liquid level rises in the glass tube. Setup A shows the highest liquid level, then C, then B (lowest). So the order from highest to lowest basin temperature is A, C, B.

Question 30

The diagram below shows four identical 300-g iron balls, A, B, C and D, hung from a metal pole (heights above the tray: A = 1.2 m, B = 1.2 m, C = 1 m, D = 1.6 m; the tray of sand is 3 m below the pole). When the strings were cut, each ball created a dent in the sand. Which of the following statement(s) is/are correct?

A  Ball C will create the deepest dent in the sand.
B  Ball D has the least amount of gravitational potential energy.
C  Balls A and B have the same amount of gravitational potential energy.

Accepted Answer

D. A, B and C. The balls are identical (same mass). The string lengths differ, so heights above the tray differ: measuring from the pole, ball C hangs the shortest string (1 m) so it is highest above the sand and falls the greatest distance, creating the deepest dent (A correct). Ball D hangs the longest string (1.6 m) so it is lowest, giving it the least gravitational potential energy relative to the sand (B correct). Balls A and B hang from equal 1.2 m strings, so they are at the same height and have the same GPE (C correct). All three are correct.

P6 Science SA2 2014 — Raffles Girls

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