Question 1

Roger planted a seed and watered it every day. He observed the growth of the seed and recorded the length of three different parts of the young plant X, Y and Z, in the table below. Based on the table above, which of the following is correct?

Accepted Answer

D. Green leaf: Z, Root: X, Shoot: Y. The root appears first (Day 3, Part X = 1 unit), then the shoot (Day 6, Part Y grows), and the green leaves appear last (Day 12, Part Z = 4). So green leaf = Z, root = X, shoot = Y.

Question 2

The diagram below shows the life cycle of an animal. Which animal is likely to have the life cycle as shown above?

Accepted Answer

D. Cockroach. The 3-stage life cycle shown (egg → nymph → adult) is incomplete metamorphosis. A cockroach undergoes incomplete metamorphosis with these three stages. Beetles and butterflies undergo complete metamorphosis (with a larva and pupa stage), and chickens hatch as chicks, not nymphs.

Question 3

Rui-En wanted to investigate the effect of the type of soil used on the growth of plants. She planted three similar plants in three pots X, Y and Z. Her teacher told her that the experiment was not a fair test. Which of the following variables make her experiment an unfair one?

Accepted Answer

B. The amount of water used was different.. To test the effect of soil type, only the soil type should differ between pots. Because the amount of water (150 ml, 300 ml, 250 ml) is also different, there are two changing variables, making the test unfair.

Question 4

What will happen if all the flowers of the plant below are plucked off?

Accepted Answer

A. The plant will not be able to reproduce.. Flowers are the reproductive organs of a plant. Without flowers, the plant cannot produce seeds and so cannot reproduce. Food is made by leaves; standing upright is supported by the stem; water and minerals are absorbed by roots.

Question 5

The diagram below shows how the roots of a tree grow wider and deeper into the soil. Which of the following best explains why the roots grow in such a way as the plant grows taller?

Accepted Answer

D. The roots need to take in more water from the soil.. As a plant grows larger, it needs more water and minerals. The roots grow wider and deeper to absorb more water (and dissolved minerals) from a larger volume of soil. Plants do not take in food from the soil — they make their own food by photosynthesis.

Question 6

Which part (1), (2), (3) or (4), makes food for the plant?

Accepted Answer

B. part (2) — leaves. Leaves contain chlorophyll, which traps light energy to make food (sugar) through photosynthesis. Part (2) points to the leaves of the plant.

Question 7

Study the flow chart below. The diagram below shows a water lily. Which of the following in the flow chart above best represents a water lily?

Accepted Answer

A. A. A water lily makes its own food (Yes), bears flowers (Yes) and grows in water (Yes), so it follows all 'Yes' paths and ends at A.

Question 8

Plants W, X and Y have characteristics as shown in the table below. A tick (✓) in the box indicates the presence of such a characteristic. Using the information above, John grouped the plants in the classification table below. What are the suitable sub-headings for Group A and Group B?

Accepted Answer

D. Group A: non-flowering plants, Group B: flowering plants. From the table, W and Y produce flowers (flowering plants), while X reproduces by spores and does not produce flowers (non-flowering plant). Group A contains X (non-flowering) and Group B contains W and Y (flowering).

Question 9

Which statement is true about most mammals?

Accepted Answer

C. They produce milk.. A defining characteristic of mammals is that they produce milk to feed their young. Not all mammals can swim, have wings (only bats do), or have four legs (e.g. humans, whales).

Question 10

Henry found an animal in a river near a forest. Which of the following characteristics should he use to identify it as a fish, a reptile or an amphibian?

Accepted Answer

B. outer body covering. Fish, reptiles and amphibians can be distinguished by their outer body coverings: fish have scales (wet), reptiles have dry scales, and amphibians have moist skin. Presence of gills cannot distinguish reptiles from amphibians; all three groups reproduce by laying eggs; and both amphibians and some reptiles can live in/near water.

Question 11

The flow chart below shows some characteristics of 4 animals. Which letter W, X, Y and Z, represents the shark?

Accepted Answer

D. Z. A shark does not give birth to live young (most lay eggs) — wait, but follow the flow: gives birth to young alive? Most sharks lay eggs but here we follow the flow chart. Shark lives in water (Yes) and breathes through gills (Yes), so following the 'Yes' arms it reaches Z. Z represents an animal that gives birth to young alive, lives in water, and breathes through gills — describing a shark in this classification.

Question 12

The diagram shows two types of fungi. Which statement is true of fungi?

Accepted Answer

B. They reproduce by spores.. Fungi (such as mushrooms and mould) are not plants — they cannot make their own food. They reproduce by spores.

Question 13

Which of the following substances has a fixed shape?

Accepted Answer

C. stone. Solids have a fixed shape. Stone is a solid. Air is a gas, while oil and water are liquids — none of them have a fixed shape.

Question 14

Study the flow chart below. Which of the following sets of questions can X, Y and Z represent?

Accepted Answer

D. X: Does it have a definite volume? Y: Is it a solid? Z: Is it magnetic?. Air (a gas) has no definite volume → X = 'Does it have a definite volume?' (No → air). Water (a liquid) has a definite volume but is not a solid → Y = 'Is it a solid?' (No → water). Copper is a solid but not magnetic, while iron is magnetic → Z = 'Is it magnetic?' (No → copper, Yes → iron).

Question 15

The container below is filled with some water. Which one of the following diagrams shows the correct position of the water level in the container when it is tilted?

Accepted Answer

C. Option (3) — water surface remains horizontal. Water (a liquid) always finds its own level — the water surface stays horizontal regardless of how the container is tilted. Option (3) is the only diagram in which the water surface is horizontal after tilting.

Question 16

The diagram shows a magnet brought near a glass block. What will happen to the glass block?

Accepted Answer

B. It will not move.. Glass is not a magnetic material, so a magnet does not attract or repel it. The glass block will not move.

Question 17

A compass has a small magnet that can rotate freely as shown. Four bar magnets were arranged such that they were attracted to one another. A compass was then placed near end P and the direction of the compass was shown below. What would be the direction of the needle if the compass was placed at Q?

Accepted Answer

C. needle pointing up. At P, the compass needle's north pole points toward end P, meaning end P is a south pole. Since the magnets are attracted to one another in a chain, the poles alternate (N–S, N–S…). Following the chain through four magnets, end Q will be a north pole, so the compass needle's north pole will point away from Q — i.e. upward in the diagram.

Question 18

Marlina placed a magnet on top of a balance as shown in Diagram 1. She brought object P close to the magnet as shown in Diagram 2. What could object P be?

Accepted Answer

D. B and D only. In Diagram 2, the balance reading drops from 60.0 g to 58.0 g — the magnet is being pulled upwards. This means object P attracts the magnet. The magnet's top pole is N, so P could be a magnet with its S pole facing the magnet (i.e. B, which has N below and S above, so S faces down toward the magnet) or a magnetic material like nickel (D). A copper bar is not magnetic; a magnet with N facing N (A) would repel, not attract.

Question 19

Which of the following is a source of light?

Accepted Answer

B. Lamp. A lamp gives off (produces) its own light, so it is a source of light. Eyes do not produce light, a mirror only reflects light, and the Moon shines by reflecting sunlight.

Question 20

Study the diagram below. The shadow of the object is formed on the screen because ____.

Accepted Answer

A. The object blocks light.. A shadow is formed when an opaque object blocks light from reaching a surface. The light from the lamp cannot pass through the object, so a dark region (the shadow) appears on the screen.

Question 21

Danny stood under a lamp as shown below. The graph below shows how the length of his shadow changed as he walked from W to different positions under the lamp. What is the path he took?

Accepted Answer

A. W → X → W → Y. Directly under the lamp at W, his shadow length is shortest (≈0). Moving away from W to X, the shadow grows (longer). Returning to W, the shadow shortens back to 0. Then walking to Y, the shadow lengthens again and continues to grow because Y is further from the lamp than X in the graph. The graph (rise–fall–rise pattern starting and dipping to zero) matches W → X → W → Y.

Question 22

John wanted to find out how materials X and Y affect the amount of light passing through each material. He placed each material in the wooden box one at a time and measured the amount of light passing through using a light sensor as shown below. Results of his experiment are shown below. Which of these set-ups should John compare for a fair test?

Accepted Answer

D. B and D only. To test how the material affects light passing through, the material must differ but the thickness t and distance d must be the same. In set-ups B and D, t = 4 cm and d = 15 cm for both, with only the material differing (X vs Y). So B and D are the fair comparison.

Question 23

A wooden block had a cone-shaped top and a cylindrical bottom. A star-shaped hole was cut through the block as shown in the diagram below. If Elaine shines a torch at the wooden block from different directions, which of the following shadows could be formed by the block?

Accepted Answer

C. A, B and C only. Light is blocked by the opaque parts of the block; the hole lets light pass through. Shining the torch from the side gives shadow A (cone on top of rectangle). Shining straight down the axis with the star-hole facing the screen gives shadow B (a shape with a star-shaped hole of light). Shining along the long axis from below gives shadow C (circle from the cylindrical end). Shadow D (a plain triangle) cannot be formed because there is no view of the block that produces only a triangle without the cylindrical/circular part.

Question 24

Kim carries some books in a clear plastic bag. The books in the plastic bag will not get wet. This is because plastic bag is ____.

Accepted Answer

D. waterproof. Waterproof means water cannot pass through. Because the plastic bag is waterproof, rain water cannot get through it to wet the books.

Question 25

Hashim boils some water in the metal pot shown below. He is able to hold the pot of boiling water using the plastic handle. This is because plastic is a ____.

Accepted Answer

C. poor conductor of heat. A poor conductor of heat does not allow heat to pass through it easily. The plastic handle prevents the heat from the hot pot from reaching Hashim's hand, so he can hold the pot safely.

Question 26

A glass containing a block of ice and some water was placed in a room. The room temperature was 25 °C. Which of the following is true about the ice in the glass?

Accepted Answer

C. It will gain heat from the surroundings.. The ice is colder than the surrounding room (25 °C), so heat flows from the warmer surroundings to the colder ice. The ice gains heat from the surroundings and melts into water (a liquid). It does not become a gas, and as a solid, ice has a definite volume.

Question 27

Study the diagram below. If test tube Y is heated, the drop of ink will ____.

Accepted Answer

C. move to the left. When the air in test tube Y is heated, it expands. The expanding air pushes the drop of ink in the connecting tube toward test tube X — i.e. to the left.

Question 28

Containers in set-ups A, B and C below are of the same size and thickness but made of different materials. The containers were filled with the same volume of water at 100 °C and left on the table. Which graph correctly shows the temperature of water in the three set-ups over a period of time?

Accepted Answer

D. Graph (4). Metals (iron) are the best conductors of heat, so the water in set-up B loses heat fastest and cools the most (lowest curve). Glass is a poorer conductor than iron, so set-up A cools more slowly than B. Wood is the poorest conductor of heat of the three, so the water in set-up C cools the slowest (highest curve). Graph (4) shows C highest, then A, then B lowest — the correct order.

P4 Science SA2 2023 — CHIJ

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