Question 1

Which part, (1), (2), (3) or (4), holds the plant upright?

Accepted Answer

C. (3). Part (3) shows the stem and roots of the plant. The roots anchor the plant in the soil, and the stem provides structural support, holding the plant upright.

Question 2

Which human system is shown in the diagram?

Accepted Answer

B. muscular system. The diagram clearly illustrates the network of muscles covering the human body, which constitutes the muscular system. The skeletal system would show bones, the circulatory system would show heart and blood vessels, and the respiratory system would show lungs and airways.

Question 3

Which one of the following properties is true for both air and a pen?

Accepted Answer

B. They take up space.. Air and a pen are both forms of matter. A fundamental property of all matter is that it occupies space. A pen is a solid and has a fixed shape and volume, but air is a gas, which cannot be seen, does not have a fixed shape, and does not have a fixed volume (it expands to fill its container).

Question 4

Which is not a characteristic of animals?

Accepted Answer

D. They can make food.. Animals are heterotrophs, meaning they obtain nutrients by consuming other organisms. They cannot make their own food through photosynthesis like plants. Growth, movement, and reproduction are all defining characteristics of animals.

Question 5

The table below shows how some living things can be grouped.
Which one of the following is the most suitable heading for group X?

Accepted Answer

A. fish. The classification chart shows 'Living Things' divided into 'fungi' and 'X'. The image provided for group X is of fish (specifically, guppies). Therefore, 'fish' is the most appropriate heading for group X, representing a category of animals.

Question 6

The diagram shows a hammer.
Metal is used to make the hammerhead of the hammer because metal
(1) can reflect light
(2) does not break easily
(3) can bend without breaking
(4) does not allow light to pass through

Accepted Answer

B. (2). Hammerheads need to be very durable and hard to withstand repeated impacts without deforming or breaking. Metal possesses high strength and toughness, meaning it does not break easily. While other options might be true for metal, they are not the primary reason for its use in a hammerhead.

Question 7

In which one of the following will the two magnets push each other away?

Accepted Answer

C. (3). Magnets repel (push each other away) when like poles face each other. 
(1) N-S faces N-S (N-S attraction).
(2) S-N faces S-N (N-S attraction).
(3) S-N faces S-N (S-S repulsion).
(4) N-S faces S-N (N-S attraction).
Therefore, option (3) shows two South poles facing each other, resulting in repulsion.

Question 8

Which one of the following is not a source of heat?

Accepted Answer

C. A woollen cap. The Sun, a lighted bulb, and a candle flame all generate and emit heat. A woollen cap is an insulator; it helps to trap existing body heat and reduce heat loss, but it does not produce heat itself.

Question 9

Andy boiled some water in a pot.
He is able to hold the pot of boiling water using the plastic handle.
This is because plastic is a ___________.

Accepted Answer

D. poor conductor of heat. Plastic is a poor conductor of heat (an insulator). This property prevents the rapid transfer of heat from the hot pot to Andy's hand, allowing him to hold the handle without being burnt. If it were a good conductor, heat would quickly transfer, making it too hot to touch.

Question 10

The diagram shows the life cycle of a plant.
What is the stage marked X?

Accepted Answer

B. seed. The diagram illustrates a plant's life cycle: Adult plant -> X -> Young plant -> Adult plant. In the life cycle of most flowering plants, the adult plant produces seeds (X), which then germinate and grow into young plants (seedlings). Eggs are typically associated with animal life cycles.

Question 11

The set-up shows light shining on a wooden ball.
Which one of the following would likely be seen on the screen?

Accepted Answer

D. (4). When light shines on an opaque, spherical object like a wooden ball, it casts a shadow that is circular in shape. Option (4) shows a solid circular shadow.

Question 12

Kate ate some food in the morning. The bar graph shows the amounts of digested and undigested food that move from organs A to E of the digestive system.
In which organ(s) is/are digestive juices produced?

Accepted Answer

C. A, C and D only. Digestive juices are produced in organs where chemical digestion occurs, leading to an increase in digested food and a decrease in undigested food. From the graph:
- Organ A: Shows a decrease in undigested food and an increase in digested food, indicating digestion. So, A produces digestive juices.
- Organ B: Shows no change in undigested or digested food, meaning no digestion occurs here.
- Organ C: Shows a further decrease in undigested food and increase in digested food. So, C produces digestive juices.
- Organ D: Shows a final decrease in undigested food and increase in digested food. So, D produces digestive juices.
- Organ E: Shows no undigested food and only digested food, implying absorption rather than digestion. 
Therefore, digestive juices are produced in A, C, and D.

Question 13

The diagrams below show parts of a system in a human body.
Which of the following are functions of this system?
A They give the body shape.
B They provide protection to important organs.
C They break down food into simpler substances.
D They carry oxygen, water, and food to all parts of the body.

Accepted Answer

B. A and B only. The diagrams display bones (rib cage and hand bones), which are components of the skeletal system. The functions of the skeletal system include giving the body its shape (A) and protecting vital internal organs (B) such as the heart and lungs. Breaking down food (C) is a function of the digestive system, and carrying substances (D) is a function of the circulatory system.

Question 14

Study the classification chart below.
Based on the chart above, which of the following best represents A, B and C?

Accepted Answer

A. A: lungs, B: Circulatory, C: bones. Let's analyze the classification chart:
- 'Respiratory' system includes 'windpipe' and 'A'. The main organ for respiration is the lungs, so A is lungs.
- The system labeled 'B' includes 'blood vessels' and 'heart'. These are key components of the circulatory system, so B is Circulatory.
- 'Skeletal' system includes 'skull' and 'C'. The skeletal system is made of bones, so C is bones.
Therefore, the best representation is A: lungs, B: Circulatory, C: bones.

Question 15

Jenny set up an experiment as shown. She used the same type of plants and placed them into four similar containers P, Q, R and S with an equal amount of water and a layer of oil.
Three days later, she measured the volume of water left in each container.
Based on the experiment, which one of the following conclusions is correct?

Accepted Answer

B. There will be the least amount of water left in R.. Transpiration, the process by which plants release water vapor through their leaves, is directly related to the surface area of the leaves. 
- Container P has a plant with few leaves.
- Container Q has a plant with a moderate number of leaves.
- Container R has a plant with many leaves, meaning the largest surface area for transpiration.
- Container S has no plant (control).
The more leaves a plant has, the greater the rate of transpiration, leading to more water loss. Thus, the plant in R will lose the most water, resulting in the least amount of water left in container R.

Question 16

Wei Loon wanted to find the amount of water taken in by a plant. He placed a plant in a measuring cylinder as shown in set-up A.
The results of his experiment were recorded in the table as shown.
The purpose of set-up B is to ___________

Accepted Answer

C. ensure that the loss of water is due to the plant only. Set-up B is a control experiment identical to set-up A but without the plant. Both set-ups have a layer of oil to minimize evaporation from the water surface. By comparing the water loss in A (plant + minimal evaporation) with B (minimal evaporation only), Wei Loon can isolate the amount of water loss specifically attributable to the plant (absorption and transpiration). This ensures that the observed water loss in set-up A is indeed due to the plant's activities.

Question 17

Two similar boxes, P and Q, have a volume of 400 cm³. A metal ball of volume 100 cm³ was placed inside box P only. Both boxes were then sealed with an air-tight cover. An additional 200 cm³ of air was pumped into both boxes P and Q using a pump.
Which one of the following shows the final volume of air in each box?

Accepted Answer

C. Volume of air in Box P (cm³): 500, Volume of air in Box Q (cm³): 600. This question likely refers to the total volume of air introduced, assuming standard conditions, rather than the volume of air occupying the container, as gases fill their containers.
For Box P: The available volume is 400 cm³ (box) - 100 cm³ (ball) = 300 cm³. If we consider the initial air in this 300 cm³ space and add an 'additional 200 cm³ of air' (implying this volume at atmospheric pressure), the total 'amount' of air effectively becomes 300 cm³ + 200 cm³ = 500 cm³. This amount of air is then compressed to fit into the 300 cm³ available space.
For Box Q: The available volume is 400 cm³. If we consider the initial air in this 400 cm³ space and add an 'additional 200 cm³ of air', the total 'amount' of air effectively becomes 400 cm³ + 200 cm³ = 600 cm³. This amount of air is then compressed to fit into the 400 cm³ available space.
However, if the question is asking for the *total volume of air measured at atmospheric pressure that has been added/is present*, then 500 cm³ for P and 600 cm³ for Q fits option C. This is a common way primary school questions interpret 'volume of air' when discussing gases being pumped into a fixed space, rather than their final occupied volume.

Question 18

Amy set up an experiment as shown below to find the volume of the plasticine.
Which one of the following steps is not necessary for her to obtain an accurate result?

Accepted Answer

C. Measure the mass of the plasticine before placing it into the water.. The experiment's goal is to determine the *volume* of the plasticine using the water displacement method.
(A) Collecting the displaced water is crucial, as the volume of displaced water equals the volume of the plasticine.
(B) The plasticine must be fully submerged to displace its entire volume of water.
(C) Measuring the *mass* of the plasticine is not required to find its *volume*. Mass and volume are distinct physical properties.
(D) Ensuring no water overflows before submerging the plasticine ensures that only the water displaced by the plasticine itself is measured, leading to an accurate result.

Question 19

Jane filled a beaker with pebbles up to the 100 cm³ mark. Next, she poured 60 cm³ of sand into that beaker. She then shook the beaker gently.
What will be the new volume of pebbles and sand in the beaker?

Accepted Answer

C. 130 cm³. Pebbles are irregular solids, and there will be empty spaces (air gaps) between them even when packed. When sand is poured into the beaker and shaken, the smaller sand particles will fill these gaps between the larger pebbles. Therefore, the total volume of the mixture will be less than the sum of their individual volumes (100 cm³ + 60 cm³ = 160 cm³). However, the sand also adds its own volume, so the total volume will be greater than 100 cm³. 130 cm³ represents a realistic combined volume where the sand fills some, but not all, of the empty spaces, and also adds to the total volume.

Question 20

Hui Ying set up an experiment as shown. She filled the syringe with some water.
What will happen to the volume of air and water when the plunger is pushed down?

Accepted Answer

A. Volume of air: decreases, Volume of water: remains the same. Air (a gas) is highly compressible because its particles are far apart. When the plunger is pushed down, the volume of the trapped air will decrease. Water (a liquid) is largely incompressible because its particles are closely packed. Therefore, the volume of water will remain essentially the same when the plunger is pushed down.

Question 21

Study the classification chart below carefully.
Which of the following correctly shows the materials that are represented by the letters D, E, F and G?

Accepted Answer

B. D: steel, E: copper, F: wood, G: rubber. The chart classifies materials based on their heat conductivity:
- 'Good Conductor of Heat' typically includes metals. Steel and copper are both good conductors of heat.
- 'Poor Conductor of Heat' (insulators) typically includes materials like wood and rubber.
Let's check the options:
(A) E: rubber (poor conductor) is listed as a good conductor - Incorrect.
(B) D: steel (good conductor), E: copper (good conductor), F: wood (poor conductor), G: rubber (poor conductor) - This matches the properties.
(C) D: wood (poor conductor) is listed as a good conductor - Incorrect.
(D) D: wood (poor conductor) is listed as a good conductor - Incorrect.
Therefore, option (B) correctly identifies the materials.

Question 22

Mr Lim heated some identical stones to 90°C and placed different number of stones into four beakers of water.
Which beaker of water will record the highest temperature?

Accepted Answer

B. B. To achieve the highest final temperature, the greatest amount of heat must be transferred to the smallest amount of water. The heat transferred from the stones is proportional to the number of stones. The heat absorbed by the water is proportional to its volume.
Let's calculate the ratio of (Number of stones / Volume of water):
- Beaker A: 2 stones / 100 ml = 0.02 stones/ml
- Beaker B: 3 stones / 100 ml = 0.03 stones/ml
- Beaker C: 1 stone / 200 ml = 0.005 stones/ml
- Beaker D: 3 stones / 400 ml = 0.0075 stones/ml
Beaker B has the highest ratio of stones to water volume, meaning the most heat will be transferred to a relatively small amount of water, resulting in the highest temperature.

Question 23

Dave wanted to find out which rod was the best conductor of heat. He placed four different rods in a container of hot water. Next, he placed a ball of wax at the top of each rod. Then, he recorded the time taken for the wax to melt.
To conduct a fair test, which of the following variables must he keep the same?
A Size of wax
B Length of rod
C Material of rod
D Time taken for the wax to melt

Accepted Answer

A. A and B only. For a fair test, only one variable should be changed (the independent variable), while all other relevant variables are kept constant (controlled variables).
- The independent variable is the 'Material of rod' (C), as Dave wants to compare the conductivity of 'different rods'.
- The dependent variable is 'Time taken for the wax to melt' (D), as this is the measurement used to assess conductivity.
- To ensure a fair comparison, the 'Size of wax' (A) must be the same, so the same amount of heat is required to melt each wax ball. 
- The 'Length of rod' (B) must also be the same, as the distance heat travels affects the rate of heat transfer. 
Therefore, A and B must be kept constant.

Question 24

Mark placed two empty identical containers, A and B, on a table. Both containers were at room temperature initially. He poured 500 cm³ of boiling water into container A and 1000 cm³ of boiling water into container B.
The temperatures of the water in A and B were recorded every minute for some time. Which of the following shows the correct graph for his results?

Accepted Answer

A. (1). Both containers start with water at 100°C. Container B has twice the volume (and thus mass) of boiling water compared to container A. A larger mass of water contains more thermal energy and will take a longer time to cool down to room temperature. Therefore, the temperature of water in container B will decrease more slowly than that in container A. Graph (1) correctly shows both temperatures starting at 100°C, with curve B (larger volume) remaining above curve A (smaller volume) as they cool, indicating that B cools slower than A.

Question 25

Ali wrapped two empty glass bottles with identical towels of different temperatures. He then set up the experiment using the bottles as shown.
What would Ali observe after 5 minutes?

Accepted Answer

C. Water entered tube P. Bubbles escaped from tube Q.. Gases expand when heated and contract when cooled.
- For tube P: The bottle is wrapped with a cold towel (5°C). The air inside the bottle will cool and contract, causing a decrease in air pressure. The higher external atmospheric pressure will then push water up into tube P.
- For tube Q: The bottle is wrapped with a hot towel (90°C). The air inside the bottle will heat up and expand, causing an increase in air pressure. This increased pressure will force air out of tube Q, resulting in bubbles escaping into the surrounding water.
Thus, water would enter tube P, and bubbles would escape from tube Q.

Question 26

Ron wanted to cool his glass of hot tea. He added ice cubes into the glass and put it into a basin of cold water as shown.
Ron observed the set-up until all the ice cubes had melted.
Which item(s) gained heat during the experiment?
A ice
B hot tea
C cold water

Accepted Answer

B. A and C only. Heat always flows from a region of higher temperature to a region of lower temperature.
- A (ice): Ice is at 0°C (or below) and will gain heat from both the hot tea and the cold water in the basin, causing it to melt.
- B (hot tea): The hot tea is the hottest component and will lose heat to the ice cubes directly and to the cold water in the basin via the glass.
- C (cold water): The cold water in the basin is colder than the hot tea (B) but warmer than the ice (A). It will gain heat from the hot tea through the glass. While it might lose some heat to the ice directly (if ice is exposed), its primary role as a heat sink for the tea means it gains heat from the tea. Therefore, A and C gained heat.

Question 27

A cat walked along a street on a dark night from position A to position C as shown below. There was only one lit lamp post on the street at position B.
Which one of the following graphs shows the length of the cat's shadow as it walked from position A to position C?

Accepted Answer

C. (3). When an object (the cat) is far from a point light source (the lamp post at B), it casts a long shadow. As the object approaches the light source, its shadow shortens. The shadow is shortest when the object is directly under the light source. As the object moves away from the light source, the shadow lengthens again.
Therefore, as the cat walks from A towards B, its shadow length will decrease. As it walks from B towards C, its shadow length will increase. Graph (3) correctly depicts this trend, showing the shadow length decreasing to a minimum at B, and then increasing towards C.

Question 28

Tom placed a ball in a box and covered the box. He made a hole at the side of the box and light could only enter through the hole. Tom then looked through the hole but could not see the ball inside the box.
Which of the following statements explains why Tom was not able to see the ball in the box?

Accepted Answer

D. There was not enough light from the ball entering Robert's eyes.. To see an object that is not a light source, light must first fall on the object, be reflected by it, and then travel into the observer's eyes. If Tom (or Robert, assuming a typo in the option for Tom) could not see the ball, it means that insufficient light reflected off the ball and passed through the hole into his eyes. The ball being opaque (option B) is a property related to shadow formation, but it doesn't directly explain not being able to see it. If light reached the ball and reflected, he would see it. So the problem is insufficient reflected light reaching the eye.

Question 29

The diagram shows a wooden toy.
Which of the following are possible shadows formed by the wooden toy?

Accepted Answer

A. A and B only. The wooden toy consists of three rectangular blocks stacked, with the base being the largest and the top being the smallest.
- If light shines from directly above the toy, the shadow formed would be the shape of the largest base, which is a solid square (A).
- If light shines from the side of the toy, the shadow would be the silhouette of its side profile, which would appear as a stepped shape (B).
Shapes C and D do not represent possible shadows of this particular toy.

Question 30

Danny conducted an experiment using two wooden blocks, E and F, of different heights to investigate the length of shadows.
The diagram shows the shadows of E and F on a screen.
Based on the above diagram, which of the following shows the correct set-up that Danny used to form the shadows?

Accepted Answer

C. (3). The initial diagram shows block E (taller) casting a shorter shadow than block F (shorter). For a shorter object to cast a longer shadow than a taller object, the shorter object must be positioned closer to the light source than the taller object. This is because light rays diverge from a light source, and an object closer to the source will block a wider angle of light, resulting in a proportionally longer shadow relative to its height.
- Set-up (3) shows block F (shorter) placed closer to the light source than block E (taller). This arrangement would result in F casting a longer shadow than E, matching the observation.

P4 Science SA2 2025 — Anglo Chinese

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