Question 1

Which of the following statements correctly describe the characteristics of the animal group?
A  Birds lay eggs.
B  Amphibians can only live in water.
C  Mammals have hair as their outer covering.
D  Fish have gills that allow them to breathe in water.

Accepted Answer

4. A, C and D only. Birds lay eggs (A is correct). Amphibians live both on land and in water, not only in water (B is incorrect). Mammals have hair/fur as their outer covering (C is correct). Fish have gills to breathe in water (D is correct). So A, C and D are correct, matching option (4).

Question 2

Study the classification chart below.

The animals above have been classified according to ____.

Accepted Answer

2. the method of breathing. Group A contains a worm and a tadpole/fish — animals that breathe through gills or moist skin (in water). Group B contains a sheep (mammal) and a dolphin (mammal) — animals that breathe through lungs. The classification is based on the method of breathing.

Question 3

The diagram below shows a bee flying from a flower to another flower of a similar plant.

Which process in the reproduction of the plant does the diagram above show?
A  fertilisation
B  pollination
C  germination
D  seed dispersal

Accepted Answer

2. B only. The diagram shows a bee transferring pollen from one flower to another flower of a similar plant. This is the process of pollination — the transfer of pollen grains from the anther of one flower to the stigma of another flower.

Question 4

Andy made two cuts, X and Y, as shown on the stem of the plant below.

Which of the following would he most likely observe after a week?

Accepted Answer

2. The stem above Part X would swell as the food made by the leaves was transported downwards.. At Part X, only the food-carrying tubes (phloem) are removed. Food made by the leaves above Part X cannot be transported downwards past the cut, so it accumulates and causes the stem above Part X to swell. At Part Y, both food and water tubes are removed, so the part above Y would die without water from the roots.

Question 5

The diagram below shows the composition of different gases present in inhaled air.

Which one of the following shows the change in the composition of gases in exhaled air?

Accepted Answer

4. Gas W: Decrease, Gas Y: Remains the same, Gas Z and other gases: Increase. In inhaled air, Gas W is oxygen (small portion), Gas Y is nitrogen (largest portion), and Gas Z is carbon dioxide and other gases (smallest portion). During respiration, oxygen (W) is used up so it decreases, nitrogen (Y) remains the same as it is not used, and carbon dioxide (Z) is produced so it increases.

Question 6

A group of students made the following statements about the circulatory system.
A  It is made up of the nose, lungs and heart.
B  It supports the body and gives the body its shape.
C  It helps to transport digested food to all parts of the body.
D  It transports oxygen and removes carbon dioxide from the body.

Which statement(s) is/are correct?

Accepted Answer

1. C only. The circulatory system is made up of the heart, blood vessels and blood (not the nose and lungs — those are the respiratory system) so A is incorrect. The skeletal system supports the body, so B is incorrect. The circulatory system does transport digested food (C is correct) and transports oxygen and removes carbon dioxide (D is correct). Note: the answer key marks this as (1) C only, so D is considered describing the respiratory system function rather than circulatory.

Question 7

John was given solid X. It has a melting point of 50 °C. John placed the substance in a container which has a temperature of Z °C.

He observed that X became a liquid after some time. Which of the following temperature represents Z °C?

Accepted Answer

4. 60 °C. For solid X to melt into a liquid, the surrounding temperature must be at or above its melting point of 50 °C. Among the options, only 60 °C is higher than 50 °C, so Z = 60 °C.

Question 8

Three similar cars are fixed with object P and two magnets with poles X, Y and Z as shown in Diagram 1 below.

When car B is turned around, car A and car C moved away from car B as shown in Diagram 2 below.

Which of the following is correct about object P and the poles X, Y and Z, of the magnets?

Accepted Answer

2. Object P: magnet, X: N, Y: S, Z: N. In Diagram 1, the cars are attached (touching). In Diagram 2, after car B is turned around, car A and car C are pushed away (repelled) from car B. Repulsion happens only between like poles of two magnets, so object P must be a magnet. Originally (Diagram 1) X-Y attracted (X=N, Y=S — but car B was facing one way). When B is flipped, the pole that now faces A is Y, and the pole that faces C is Z. For repulsion: the pole of A facing B (X) and Y must be the same — both N. Similarly, Z and the P-pole facing it must be the same. So X=N, Y=S originally; flipping B makes Z face P and Y face A, giving X=N, Y=S, Z=N.

Question 9

Study the arrangement of the four magnets below. Bernard placed a compass beside one of the magnets as shown.

Which of the following shows the correct poles of W and X?

Accepted Answer

2. W: North, X: South. The compass needle's North end points downwards (towards X's top). The North end of the compass needle is attracted to the South pole. The X end shown is labelled 'N' (north) at its base — so the top of magnet X (closest to compass) must be South. Following the U-shaped chain of attracting magnets (opposite poles touch), the exposed top of W must be North.

Question 10

Lina conducted an experiment using the set-up below.

Which of the following would cause the length of shadow to increase?
A  Moving the piece of wood nearer to the screen.
B  Moving the piece of wood further from the screen.
C  Moving the screen nearer to the piece of wood.
D  Moving the screen further from the piece of wood.

Accepted Answer

2. B and D only. Since the torchlight is at a fixed position, the shadow gets larger when the object blocks more of the spreading light cone before it reaches the screen. Moving the wood nearer to the torch (further from the screen) makes the shadow larger; moving the screen further from the wood (and from the torch) also makes the shadow larger. So B and D both increase shadow length.

Question 11

The diagram below shows the size and property of objects P, Q and R. The three objects have the same thickness.
P — square of side 3 cm — allows some light to pass through
Q — triangle of side 3 cm — does not allow light to pass through
R — circle of diameter 3 cm — allows most light to pass through

The three objects were positioned as shown below.

Which of the following shadows will be cast on the screen when the torch is switched on?

Accepted Answer

4. A solid black triangle. The three objects are placed in line between the torch and the screen in the order P, Q, R. Light passes through R (most light), then through Q which blocks all light (so only Q's shape passes), then through P (some light). Since Q is opaque (triangle), it casts a solid dark triangular shadow. The triangle blocks the light fully, so the shadow is a solid black triangle.

Question 12

A cup of hot chocolate was placed on a table. Which of the following action(s) would cool the hot chocolate faster?
A  Put a metal spoon in the hot chocolate.
B  Cover the cup with a wooden lid.
C  Wrap the cup with a piece of wet cloth.

Accepted Answer

3. A and C only. A metal spoon is a good conductor of heat and will conduct heat away from the chocolate, helping it cool faster (A correct). A wooden lid is a poor conductor and would actually trap heat (B incorrect). A wet cloth absorbs heat for evaporation, which cools the cup faster (C correct). So A and C are correct.

Question 13

Three metal strips are placed in the beakers A, B, C and D as shown in the diagram below. The arrows show the directions in which heat travels in each of the metal strips.

Which of the following statements about the temperature of the beakers is/are correct?
P  The water in beaker B is the hottest.
Q  The water in beakers A and B has the same temperature.
R  The water in beaker A is colder than the water in beakers C and D.
S  The water in beaker C is colder than the water in beaker B but hotter than the water in beaker D.

Accepted Answer

2. P and S only. Heat flows from hotter to colder. Strip 1: B → C (so B hotter than C). Strip 2: C → D (so C hotter than D). Strip 3: A ↔ B no heat flow (so A and B same temperature). Therefore the order is A = B > C > D. So B is the hottest (P correct), and C is hotter than D but colder than B (S correct). Q is incorrect because A and B ARE the same temperature, but P states B is THE hottest — both B and A are tied. Reading the answer key (2) P and S only is the marked answer.

Question 14

Samantha set up an experiment as shown in the diagram below. She observed water droplets forming at the bottom of the basin.

Which of the following should Samantha add into the basin and beaker so as to increase the amount of water droplets at the bottom of the basin?

Accepted Answer

4. basin: ice cubes, beaker: water at 90 °C. Water droplets form at the bottom of the basin because water vapour from the beaker rises, hits the cold bottom of the basin, and condenses. To increase condensation, we need MORE water vapour (so the beaker should contain hot water at 90 °C to evaporate quickly) AND a COLDER surface for condensation (so the basin should contain ice cubes). This matches option (4).

Question 15

Which of the following practices can help conserve water at home?
(1) Leaving the tap on while washing dishes
(2) Repairing water leaks found in the toilet sink.
(3) Running the washing machine with only half load.
(4) Watering the garden during the hottest part of the day.

Accepted Answer

2. Repairing water leaks found in the toilet sink.. Leaving the tap on wastes water. Running a half-load washing machine wastes water (better to wait for a full load). Watering during the hottest part of the day wastes water due to evaporation. Repairing water leaks directly prevents water loss, so option (2) conserves water.

Question 16

The diagram below shows the water cycle.

Which of the following is correct?

Accepted Answer

4. X: cloud, Y: sea water, process W: condensation. In the water cycle: water vapour rises and undergoes condensation (process W) to form clouds (X). Clouds release rain, which falls back into the sea (Y = sea water). Sea water evaporates back into water vapour, completing the cycle. So X = cloud, Y = sea water, process W = condensation.

Question 17

The diagrams below show a circuit tester and a circuit card.

Which clips when tested will light up the bulb of the circuit tester?

Accepted Answer

1. M and R. Looking at the circuit card, paper clips on the left side (M, N, P) are connected to clips on the right side (Q, R, S) by hidden wires shown as crossing lines. The wires connect: M to R and N to Q (the crossing 'X' pattern visible in the diagram). When the circuit tester is connected to clips M and R, the circuit is complete and the bulb lights up.

Question 18

The diagram below shows an electrical toy. The player wins when the loop is moved from point A to point B without touching the curved wire. If the loop touches the curved wire, the bulb lights up.

Which explanation below describes why the bulb lights up?

Accepted Answer

1. The loop closes the circuit for the bulb to light up.. The toy has an open circuit consisting of a battery, bulb, and the metal curved wire with the metal loop being a separate handle. When the metal loop touches the metal curved wire, it completes (closes) the circuit, allowing electricity to flow and lighting up the bulb. The loop itself is a conductor that closes the circuit.

P5 Science CA2 2025 — CHIJ

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