Question 1

Which one of the following statements is true for all insects?
(1) They live on land.
(2) They have wings.
(3) They have scales.
(4) They have six legs.

Accepted Answer

D. They have six legs.. All insects share the defining characteristic of having six legs. Not all insects live exclusively on land, have wings, or have scales, but six legs is a universal feature of the insect class.

Question 2

The graph shows the length of each stage in the life cycle of organisms S and T. Which statement is correct?
(1) S spent the shortest time as a pupa in its life cycle.
(2) T was at the larva stage 10 days after the egg hatched.
(3) T took a shorter time to become an adult as compared to S.
(4) T spent a total of 12 days more than S at the egg and larva stage.

Accepted Answer

C. T took a shorter time to become an adult as compared to S.. Total time for S = 8 + 12 + 14 = 34 days. Total time for T = 2 + 6 + 4 = 12 days. T takes a shorter time to become an adult than S. Option 1 is wrong (S spent the longest at pupa, 14 days). Option 2 is wrong (T's larva is at days 2-8). Option 4 is wrong (S egg+larva = 20, T = 8, so S spent 12 more days than T).

Question 3

Accepted Answer

B. Question A: Does it have hair? | Question B: Does it live in water? | C: moss. Both dolphin and elephant have hair (mammals), so Question A is 'Does it have hair?'. Dolphin lives in water but elephant does not, so Question B is 'Does it live in water?'. C must be an organism that cannot make its own food and is not a mammal — moss makes its own food (eliminating mushroom path requires no food-making → 'Yes' branch). Re-reading: 'Can make its own food?' No → bacteria; Yes → C. So C makes its own food and is not animal. Moss fits (it is a plant that makes food). Answer is (2).

Question 4

Which statement is not true about animals?
(1) They can grow.
(2) They can move.
(3) They can reproduce.
(4) They can make food.

Accepted Answer

D. They can make food.. Animals cannot make their own food; only plants (and some other producers) can make food through photosynthesis. Animals must consume other organisms for food. They can grow, move and reproduce.

Question 5

Alan wanted to know if substance T could keep ants away. He conducted an experiment using two identical glass containers A and B. In container A, he put some ants, food and substance T as shown below. Which diagram below correctly shows what Alan must put into glass container B to carry out a fair test?
(1) [Container with ants on left and substance T only on right]
(2) [Container with only food on right]
(3) [Container with only ants on left and food at the bottom]
(4) [Container with ants on left and food only on right]

Accepted Answer

D. Container with ants and food only (no substance T). For a fair test, all variables except the one being tested (substance T) must be kept the same. Container B must contain ants and food (identical to A) but without substance T, so any difference in ant behaviour can be attributed to substance T.

Question 6

Sam made the following observations about the life cycle of an animal.
• There are three stages in the life cycle.
• The young looks like the adult.
Which animal was Sam observing?
(1) Frog
(2) Beetle
(3) Butterfly
(4) Grasshopper

Accepted Answer

D. Grasshopper. A grasshopper has three life-cycle stages (egg → nymph → adult) and the nymph (young) resembles the adult. Frogs have 3-4 stages with young (tadpole) looking different. Beetles and butterflies have 4 stages with young (larva) looking different from the adult.

Question 7

The diagram below shows the life cycle of a plant. What is the stage marked X?
(1) egg
(2) seed
(3) adult plant
(4) young plant

Accepted Answer

C. adult plant. In the plant life cycle, the stage that produces seeds (after the young plant grows) is the adult plant. X is the larger plant that produces the seed in the cycle.

Question 8

Which human system is shown in the diagram? 
(1) skeletal system
(2) muscular system
(3) circulatory system
(4) respiratory system

Accepted Answer

A. skeletal system. The diagram shows the bones of a human body, which makes up the skeletal system.

Question 9

Which of the following is a correct function of the roots?
(1) keeps the plant upright
(2) takes in light for the plant
(3) makes food for the plant
(4) holds the plant firmly to the soil

Accepted Answer

D. holds the plant firmly to the soil. Roots anchor the plant firmly in the soil. They also absorb water and mineral salts. They do not take in light or make food (those are functions of leaves), and the stem (not roots) keeps the plant upright.

Question 10

The diagram below shows a young plant. The leaf helps the plant to ____.
(1) make food
(2) grow upright
(3) absorb water
(4) absorb mineral salts

Accepted Answer

A. make food. Leaves contain chlorophyll and carry out photosynthesis, making food for the plant. Water and mineral salts are absorbed by the roots, and the stem provides upright support.

Question 11

Which one of the following properties is true for both air and a pencil?
(1) They can be seen
(2) They take up space
(3) They have fixed shapes
(4) They have fixed volumes

Accepted Answer

B. They take up space. Both air (gas) and a pencil (solid) take up space (have volume). Air cannot be seen, has no fixed shape and no fixed volume. The pencil has a fixed shape and volume but air does not, so only 'they take up space' is true for both.

Question 12

Which of the following objects is not made of waterproof material?
(1) metal spoon
(2) bathroom towel
(3) rubber gloves
(4) plastic umbrella

Accepted Answer

B. bathroom towel. A bathroom towel is made of absorbent fabric (cotton) that soaks up water, so it is not waterproof. Metal, rubber and plastic are all waterproof materials.

Question 13

Ling Ling heated some dumplings with filling in the steamer as shown in Diagram 1. After a while, the filling burst through the skin of the dumpling as shown in Diagram 2. [Figure: A dumpling with the filling bursting out through its skin.] Which of the following best explains why?
(1) The filling is hotter than the skin of the dumpling.
(2) The skin of the dumpling is hotter than the filling.
(3) The filling expanded more than the skin of the dumpling.
(4) The skin of the dumpling contracted more than the filling.

Accepted Answer

C. The filling expanded more than the skin of the dumpling.. When heated, both the filling and the skin gain heat and expand. The filling expanded more than the skin could stretch, causing the skin to burst open.

Question 14

The diagram below shows a mattress protector covering a mattress. It prevents spills and sweat from being absorbed by the mattress. Which of the following statements explain why the mattress protector is able to protect the mattress?
A. It is flexible.
B. It is waterproof.
C. It can float in water.
D. It is a poor conductor of heat.
(1) A and B only
(2) A and D only
(3) B and C only
(4) C and D only

Accepted Answer

A. A and B only. The mattress protector must be flexible (A) to wrap around the mattress and conform to its shape, and waterproof (B) to prevent spills and sweat from being absorbed. Floating in water and being a poor conductor of heat are not relevant to protecting a mattress from spills.

Question 15

Study the set-up in the diagram below. The volume of the container is 900 cm³. It contains 300 cm³ of water. An additional 200 cm³ of air was pumped into the container. Which of the following states the volume of air in the container and the reading on the electronic balance?
(1) Volume of air: 300 cm³ | Reading: 800 g
(2) Volume of air: 600 cm³ | Reading: More than 800 g
(3) Volume of air: 500 cm³ | Reading: 800 g
(4) Volume of air: 800 cm³ | Reading: More than 800 g

Accepted Answer

B. Volume of air: 600 cm³ | Reading: More than 800 g. The container is sealed. Initial air volume = 900 - 300 = 600 cm³. The container volume cannot increase, so the air still occupies 600 cm³ but is compressed at higher pressure. Since air has mass, pumping in additional air increases the total mass, so the reading is more than 800 g.

Question 16

The length of David's shadow near a lamp post over some time is as shown below. What was David doing during that time?
(1) walking towards the lamp post
(2) standing still near the lamp post
(3) walking away from the lamp post
(4) jumping up and down near the lamp post

Accepted Answer

B. standing still near the lamp post. The shadow length remained constant, meaning David's distance from the lamp post did not change. Walking towards/away would change the shadow length; jumping would also change the shadow length. Therefore David was standing still.

Question 17

Ling has a toy train as shown in Diagram 1. When she turned carriage A around, it moved together with carriage B to the right and the engine moved away to the left as shown in Diagram 2. [Figure: Engine moved to the left while carriages A (now with pole K on left, object Z, pole J area) and B (pole L of magnet on left) moved to the right.] Which of the following is correct about object Z and the poles, J, K and L, of the magnets?
(1) Z: magnet | J: S | K: S | L: N
(2) Z: copper | J: N | K: N | L: S
(3) Z: iron | J: S | K: N | L: S
(4) Z: iron | J: N | K: N | L: S

Accepted Answer

A. Z: magnet | J: S | K: S | L: N. In Diagram 1, J attracts Z (engine sticks to carriage A) and K attracts L (carriages A and B stick). In Diagram 2, after flipping A, the engine is repelled from Z (so Z must be a magnet whose newly-facing pole repels J — Z must be a magnet, not iron/copper which only attract). K-L still attract because K now faces away. Only option (1) has Z as a magnet, consistent with the repulsion observation after flipping carriage A.

Question 18

Bala compared the masses of three objects, J, K and L, using two similar balances. What could Bala conclude based on his observations?
(1) Object J has the least mass
(2) Object K has less mass than Object J
(3) Object J and object L have the same mass
(4) The mass of object L is the total mass of object J and object K

Accepted Answer

A. Object J has the least mass. Left balance: K is heavier than J (K side goes down). Right balance: L is heavier than K (L side goes down). So L > K > J, meaning J has the least mass.

Question 19

The graph below shows the amount of undigested food entering parts of the human digestive system. Which of the following correctly shows the part of the human digestive system represented by A, B, C or D?
(1) stomach: A | large intestine: B | small intestine: C
(2) stomach: B | large intestine: C | small intestine: A
(3) stomach: C | large intestine: A | small intestine: D
(4) stomach: D | large intestine: B | small intestine: A

Accepted Answer

A. stomach: A | large intestine: B | small intestine: C. The order of food through the digestive system is mouth → stomach → small intestine → large intestine. Most digestion and absorption occurs in the small intestine, leaving the least amount of undigested food. So after mouth, A = stomach, B = small intestine... Re-examining: as food moves through, undigested amount generally decreases (lots absorbed). The smallest amount is after the small intestine (greatest absorption). C has the least amount, so C is after small intestine. Order: mouth (most) → A (stomach) → B (small intestine — lots absorbed) → C (after small intestine = least, actually large intestine here) — this doesn't perfectly fit. Based on the marking key answer = 1, A = stomach, B = small intestine, C = large intestine in the typical PSLE flow.

Question 20

Sally conducted an experiment using two set-ups, 1 and 2, as shown below. The ice cubes and the blocks used were of the same size and thickness. Both blocks were at room temperature before the start of the experiment. She observed that the ice cube in set-up 1 melted completely in 15 minutes, while the ice cube in set-up 2 melted completely in 5 minutes. Which of the following can Sally conclude from the experiment?
A. Both ice cubes lost heat to the blocks.
B. Both ice cubes gained heat from the blocks.
C. Heat will flow through Material Y faster than Material Z.
(1) A only
(2) B only
(3) A and C only
(4) B and C only

Accepted Answer

B. B only. Ice melts when it gains heat. The blocks are at room temperature (warmer than ice), so heat flows from blocks to ice. Statement B is correct. Statement C is wrong because Z melted the ice faster, meaning heat flowed through Z faster than Y, not Y faster than Z. So only B is correct.

Question 21

Warm water at 80°C is mixed with cold water at 5°C. What is a possible final temperature of water in the beaker?
(1) 5°C
(2) 50°C
(3) 80°C
(4) 85°C

Accepted Answer

B. 50°C. When warm water (80°C) and cold water (5°C) mix, heat flows from warm to cold until they reach the same temperature. The final temperature must be between 5°C and 80°C. Only 50°C fits this range.

Question 22

Siva prepared a set-up with two torches and a cylindrical block. The diagram below shows the top view of the set-up. He turned on the torches and two shadows, X and Y, were cast on the screen. Which one of the following correctly shows the shadows cast on the screen?
(1) Two shadows of equal height, both rectangular
(2) Shadow X shorter, Shadow Y taller (both rectangular)
(3) Shadow X shorter, Shadow Y taller (similar to option 2)
(4) Shadow X taller, Shadow Y shorter

Accepted Answer

B. Shadow X shorter, Shadow Y taller. The torch closer to the block casts a larger shadow (Y), and the torch further from the block casts a smaller shadow (X). Both shadows are rectangular because the side profile of the cylindrical block facing the screen is rectangular. The shadow X is therefore shorter and Y is taller — option (2) correctly shows this.

Question 23

Imran placed two empty identical containers, S and T, both initially at room temperature on a table. He then poured 500 cm³ of 8°C water into container S and 250 cm³ of 8°C water into container T. The temperature of water in S and T were recorded every minute for some time. Which one of the following is the correct graph for his results?
(1) S warms first then T, both reach the same final temperature
(2) T warms faster than S, both reach the same final temperature
(3) S warms faster, T reaches a lower final temperature
(4) S warms first then T, both reach the same final temperature (similar to 1)

Accepted Answer

B. T warms faster than S, both reach the same final temperature. T has less water (250 cm³) than S (500 cm³). The smaller volume of water in T gains heat from the surroundings faster, so T warms up faster than S. Both will eventually reach room temperature (same final temperature). Graph (2) correctly shows T rising faster than S to the same plateau.

Question 24

Wendy has three sheets of different materials, each with a different shape. One sheet is made of a material that allows some light to pass through. While the other two of the sheets are made of the same material. She conducted an experiment in a dark room using the setup below. [Figure: Light source on left, then sheet X, sheet Y, sheet Z in a row, then screen on right.] Which of the following could be seen on the screen?
(1) Triangle shape visible inside a circular faint glow
(2) Square inside a circle
(3) Square only
(4) Triangle shape visible inside a faint circular glow

Accepted Answer

D. Triangle visible inside a faint circular glow (X translucent). If sheets Y (triangle) and Z (square) are the same opaque material, no light passes through them; their shadows would normally be cast. Sheet X (circle) must be the translucent one that allows some light to pass through. The light passes through X (circle outline visible as a glow), is blocked by Y (triangle silhouette) and Z (square silhouette). Since Y is between X and Z, the triangle silhouette appears on the screen as a sharp dark shape inside the faint circular glow from X. Option (4) shows the triangle silhouette inside a circular glow.

P4 Science SA2 2025 — Methodist Girls

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