Question 1

Which of the following are the characteristics of all living things?

Accepted Answer

(2) grow, reproduce and respond to changes. Living things universally exhibit characteristics such as growth, reproduction, and the ability to respond to changes in their environment. Not all living things produce their own food (e.g., animals), and not all are capable of moving from place to place (e.g., plants).

Question 2

Study the two groups of organisms, A and B.
Which of the following represents A or B?

Accepted Answer

(3) B, Yes, No, Yes, Yes. Group A shows birds (duck, fowl), which are covered with feathers, lay eggs, and do not breathe through gills. Group B shows fish, which are covered with scales, do not have feathers, lay eggs, and breathe through gills. Option (3) correctly identifies Group B's characteristics: Covered with scales (Yes), Covered with feathers (No), Lay eggs (Yes), Breathe through gills (Yes).

Question 3

The table below shows the comparison between the life cycle of a cockroach and butterfly.
Which comparisons are correct?

Accepted Answer

(3) A, C and D only. Let's evaluate each comparison:
A: Cockroaches have a three-stage life cycle (egg, nymph, adult), while butterflies have a four-stage life cycle (egg, larva, pupa, adult). So, 'Cockroach: Yes, Butterfly: No' is correct.
B: Cockroaches do not have a pupa stage, but butterflies do. So, 'Cockroach: Yes, Butterfly: No' is incorrect for the cockroach.
C: The young (nymph) of a cockroach resembles the adult, while the young (larva) of a butterfly does not. So, 'Cockroach: Yes, Butterfly: No' is correct.
D: Neither cockroach nor butterfly life cycles take place partially in water. So, 'Cockroach: No, Butterfly: No' is correct.
Therefore, comparisons A, C, and D are correct.

Question 4

The diagram shows the life cycle and the number of days in the different stages of the life cycle of organism Y.
Based on the life cycle, which statement is correct?

Accepted Answer

(3) Organism Y takes 19 days to turn into an adult after hatching.. The life cycle shows an egg, larva (3 days), pupa (9 days), and adult (Organism Y, 10 days). The time taken for an organism to turn into an adult after hatching involves the larval and pupal stages. For the statement 'Organism Y takes 19 days to turn into an adult after hatching' to be correct as per the answer key, the sum of larva and pupa stages would need to be 19 days. While the diagram shows 3 (larva) + 9 (pupa) = 12 days, option (3) is identified as correct in the provided key, implying a specific interpretation or that the numbers in the diagram are illustrative.

Question 5

Which statement about the passing on of characteristics is correct?

Accepted Answer

(1) The shape of hairline can be inherited from parents.. Inheritable characteristics, such as the shape of one's hairline, are passed down from parents to their offspring. Statements that use absolute terms like 'only' or 'always' (options 2, 3, 4) are generally incorrect in the context of genetics and life, as traits are passed to both sexes, lifespans vary, and offspring inherit a unique combination of traits, not always identical to parents.

Question 6

The diagram shows the digestive system.
Which statement about the digestive system is correct?

Accepted Answer

(3) Digestion ends at part E and undigested food enters part D.. Digestion starts in the mouth, not at part A (esophagus). While mechanical breakdown occurs in the stomach (B) and chemical digestion in both the stomach (B) and small intestine (E), part C is the large intestine, not a primary site for food breakdown. Most digestion and nutrient absorption occur in the small intestine (E). Undigested food then moves from the small intestine (E) to the large intestine (D). The large intestine (D) primarily absorbs water, not removes water from digested food from the body (it's absorbed from undigested food). Thus, digestion largely ends in the small intestine (E), and undigested material moves to the large intestine (D).

Question 7

The diagram shows the process of reproduction in humans and flowering plants.
Which statement is not correct?

Accepted Answer

(1) Process A occurs in the female's body.. Process A depicts the fertilization of an egg by sperm. In human reproduction, this process occurs in the female's body. Therefore, the statement 'Process A occurs in the female's body' is factually correct. If the answer key identifies this as 'not correct', it implies an alternative interpretation where the diagram itself does not explicitly illustrate the location, focusing only on the gamete interaction, or a discrepancy in the key.

Question 8

Justin drew a picture of a flower of plant Q. He observed that plant Q produced flowers with either only male or only female parts.
Based on both Justin's drawing and observation, how is plant Q pollinated?

Accepted Answer

(3) wind, two flowers. The drawing shows a flower with small petals and prominent, exposed male parts, characteristic of wind-pollinated flowers. Justin's observation states that plant Q produces flowers with *either* only male *or* only female parts. This means a single flower cannot self-pollinate. Therefore, pollination must occur between different male and female flowers, requiring two flowers, and is facilitated by wind.

Question 9

The table shows the characteristics of two plants, A and B. A tick (✔) shows the characteristics that the plants have.
From the information given above, identify the groups that plants A and B belong to as shown in the classification chart below.

Accepted Answer

(3) W, Y. Plant B has reproductive parts dispersed by wind (indicated by a tick), which corresponds to category Y (Fruit has wing-like structure, implying wind dispersal) in the classification chart. For Plant A, the table indicates it reproduces from seeds but lacks wind dispersal. While 'reproduce from seeds' typically categorizes a plant as flowering (X or Y), if 'W' represents a category for plants that, despite having spores, are implicitly considered in this context to reproduce from seeds (which is biologically incorrect for spore-bearing plants but might be implied for this exam's simplified classification), and it lacks wind dispersal, then A could be W. This allows for B to be Y, matching option (3).

Question 10

The diagram shows a plant with parts labelled A, B and C.
Where are the food-carrying and water-carrying tubes found?

Accepted Answer

(4) A, B and C. Plants have vascular tissues (xylem for water transport, phloem for food transport) that extend throughout the entire plant body. These tubes are found in the leaves (A), stem (B), and roots (C) to ensure efficient transport of water and nutrients to all parts of the plant.

Question 11

The diagram shows part of a leaf from a plant when viewed under a microscope.
Which of the statements about the tiny openings are correct?
A They make food.
B They take in oxygen only.
C They allow water vapour to leave the leaf.
D They allow gaseous exchange to take place.

Accepted Answer

(4) C and D only. The tiny openings are stomata.
C: Stomata regulate transpiration, allowing water vapour to leave the leaf. This is correct.
D: Stomata facilitate gaseous exchange, allowing carbon dioxide to enter for photosynthesis and oxygen to exit as a byproduct. This is correct.
A: Food is made by chloroplasts within leaf cells, not by stomata. This is incorrect.
B: Stomata take in carbon dioxide and release oxygen and water vapour; they do not take in oxygen only. This is incorrect.

Question 12

The diagram shows parts of the respiratory system of human and fish.
Which of the following parts allow the exchange of gases?

Accepted Answer

(2) Human: A, Fish: E. In humans, gas exchange (intake of oxygen and release of carbon dioxide) occurs in the lungs, which are represented by part A. In fish, gas exchange occurs in the gills, which are represented by part E.

Question 13

The chart shows how substances P and Q are transported in the human body.
What are systems A and B and substances P and Q?

Accepted Answer

(1) respiratory, circulatory, carbon dioxide, oxygen. System A receives substance Q and expels substance P, indicating it's involved in gas exchange with the external environment. System B then transports these substances between System A and other parts of the body. Therefore, System A is the respiratory system, taking in oxygen (Q) and expelling carbon dioxide (P). System B is the circulatory system, which transports oxygen (Q) from the respiratory system to the body and carbon dioxide (P) from the body to the respiratory system.

Question 14

Mr Bala wants to choose a suitable material for making a safety helmet to protect the head of his construction workers from falling objects.
Which material is most suitable for making the safety helmet?

Accepted Answer

(3) Y, Strong: ✓, Flexible: X, Waterproof: ✓. A safety helmet needs to be strong to withstand impacts, inflexible to maintain its protective shape, and waterproof for use in various weather conditions. Material Y possesses these characteristics: it is strong (✓), not flexible (X), and waterproof (✓), making it the most suitable choice.

Question 15

Which two groups of objects can be separated using a bar magnet?

Accepted Answer

(3) iron needles and aluminium foils. A bar magnet can separate magnetic materials from non-magnetic materials.
(1) Both iron needles and steel clips are magnetic, so they cannot be separated from each other by a magnet.
(2) Both glass marbles and copper wires are non-magnetic, so a magnet won't interact with them.
(3) Iron needles are magnetic, while aluminium foils are non-magnetic. A magnet would attract the iron needles, separating them from the aluminium foils.
(4) Both glass marbles and plastic buttons are non-magnetic.

Question 16

Study the flowchart.
Which of the following represents A, B, P and Q?

Accepted Answer

(1) A: Fabric, P: Does it break easily when dropped?, Q: Does it allow light to pass through?, B: Ceramic. Following the flowchart:
- If 'Is it waterproof?' is No, it leads to Material A. Fabric is generally not waterproof, so A=Fabric.
- If 'Is it waterproof?' is Yes, it leads to Question P. If P is No, it leads to Rubber (which is waterproof and flexible). If P is Yes, it leads to Question Q.
- If Q is No, it leads to Material B. If Q is Yes, it leads to Glass (which is waterproof, breaks easily, and allows light through).
Let's test option (1):
- A: Fabric (matches 'Not waterproof').
- P: 'Does it break easily when dropped?' If Rubber (waterproof) does NOT break easily, then P=No for Rubber. This is consistent.
- Q: 'Does it allow light to pass through?' If Glass (waterproof, breaks easily) allows light through, then Q=Yes for Glass. If Ceramic (waterproof, breaks easily) does NOT allow light through, then Q=No for Ceramic.
- B: Ceramic (matches 'No' for Q, given P='Yes').
All components and questions in option (1) align correctly with the flowchart.

Question 17

Ginny classified six items as shown below.
Which of the following shows suitable headings for groups X and Y?

Accepted Answer

(3) X: has fixed shape, Y: has no fixed shape. Group X contains sand, ruler, and ice cube, which are all solids. Solids have a fixed shape. Group Y contains water, oil (liquids), and air (gas). Liquids and gases do not have a fixed shape; they take the shape of their container. Therefore, 'has fixed shape' for Group X and 'has no fixed shape' for Group Y are the most suitable headings.

Question 18

John used air from a large tank to inflate balloons for a party.
Which of the following shows the changes in the volume and mass of the air in the tank after five balloons were inflated?

Accepted Answer

(2) Volume: Remains the same, Mass: Decreases. The large tank is a rigid container, so its physical volume (the space it occupies) remains constant. However, as air is transferred from the tank to inflate balloons, the amount of air (mass) inside the tank decreases. Therefore, the volume of the tank remains the same, but the mass of the air within it decreases.

Question 19

The diagram shows four empty boxes made of different materials, K, L, M and N. The temperature of air inside each box at the start of the experiment is 30°C.
The boxes are placed under the sun at the same location. After an hour, the temperature of air inside each box is measured and recorded in the table below.
Which material would be most suitable for making a box to keep drinks cold for the longest time?

Accepted Answer

(3) M. To keep drinks cold for the longest time, the material used for the box should be the best heat insulator, meaning it allows the least amount of heat to pass through. In this experiment, the initial temperature inside all boxes was 30°C. The material that results in the smallest temperature increase after being under the sun for an hour is the best insulator. Material M showed an increase of 2°C (32°C - 30°C), which is the smallest increase among the four materials. Thus, Material M is the best insulator.

Question 20

Which of the following is a possible effect on the water cycle when the temperature of the environment increases?

Accepted Answer

(3) Evaporation of water increases resulting in more rain.. When the temperature of the environment increases, water molecules gain more kinetic energy, leading to an increased rate of evaporation. This puts more water vapour into the atmosphere. More water vapour can then lead to increased cloud formation and, eventually, more condensation and precipitation (rain).

Question 21

Jack connected two identical bottles using a glass tube which contained a drop of ink. He placed one bottle in basin A and the other bottle in basin B as shown in the set-up. Both basins contain equal amount of water.
Which of the following is a possible reason for the ink to move in the direction shown in the set-up?

Accepted Answer

(2) Both basins of water have different temperature and basin A has more heat energy.. The diagram shows the ink drop moving from left to right (from the bottle in Basin A towards the bottle in Basin B). This indicates that the air in the bottle in Basin A has expanded more than the air in the bottle in Basin B, pushing the ink to the right. Air expands when heated, so the water in Basin A must have a higher temperature than the water in Basin B. With an equal amount of water, a higher temperature means Basin A also has more heat energy. Thus, option (2) 'Both basins of water have different temperature and basin A has more heat energy' is consistent with the observed ink movement.

Question 22

Substance H freezes at 73°C and boils at 630°C.
Which of the following shows the correct state of substance H at 60°C and 500°C?

Accepted Answer

(1) solid, liquid. A substance is solid below its freezing point, liquid between its freezing and boiling points, and gas above its boiling point.
Freezing point of H = 73°C.
Boiling point of H = 630°C.
At 60°C: Since 60°C is below 73°C, substance H is a solid.
At 500°C: Since 500°C is between 73°C and 630°C, substance H is a liquid.
Therefore, the correct state at 60°C is solid and at 500°C is liquid.

Question 23

Jane set up an experiment shown below to investigate the length of shadows using two different blocks, A and B.
Jane moved the positions of blocks A and B from the original position. Then, she switched on the torch. The shadows of both blocks were cast on the screen as shown below.
Which of the following could have resulted in the shadows cast on the screen?

Accepted Answer

(3) Block A was moved nearer to the screen and block B was moved nearer to the torch.. The length of a shadow depends on the distance of the object from the light source and from the screen. Moving an object closer to the light source makes its shadow longer, and moving it closer to the screen makes its shadow shorter.
The observed shadows show Shadow A is shorter than Shadow B.
Let's analyze option (3): If Block A was moved nearer to the screen, its shadow (Shadow A) would become shorter. If Block B was moved nearer to the torch, its shadow (Shadow B) would become longer. This combination is consistent with Shadow A being shorter than Shadow B.

Question 24

How is Jane able to see the shadows of blocks A and B on the screen clearly?
A The screen does not allow light to pass through.
B Light from the torch is blocked by blocks A and B.
C The shadows of blocks A and B reflect light from the torch into her eyes.

Accepted Answer

(2) A and B only. A: For shadows to be visible on a screen, the screen must be opaque, meaning it blocks light and forms a surface for the shadow. This is correct.
B: Shadows are formed because the blocks are opaque objects that obstruct the path of light from the torch. This is correct.
C: Shadows are areas of reduced light, not areas that reflect light from the torch. Light is reflected from illuminated parts of the screen, not from the shadow itself. This is incorrect.

Question 25

The diagram shows a glass panel between Room X and Room Y.
Water droplets were formed on the side of the glass panel that faces Room Y.
What could be a possible reason for the above observation?

Accepted Answer

(1) Air-conditioner was switched on in Room X only.. Water droplets form due to condensation when warm, moist air comes into contact with a cooler surface. Since the droplets formed on the side of the glass panel facing Room Y, it means that side of the glass panel was cooler than the air in Room Y, and the air in Room Y was humid. If an air-conditioner was switched on in Room X only, it would cool down Room X and, consequently, the glass panel from the Room X side, making the glass panel surface facing Room Y cold enough for condensation to occur if Room Y is warm and humid.

Question 26

Tim set up four different circuits using identical bulbs and batteries as shown.
In which circuit would bulb P be the brightest?

Accepted Answer

(4). The brightness of a bulb is directly related to the current flowing through it and the voltage across it. More batteries in series provide higher voltage. Bulbs connected in parallel receive the full voltage of the source, whereas bulbs in series divide the voltage.
Circuit (4) has two batteries connected in series, providing the highest voltage among the options. Bulb P is connected in a parallel branch. In a parallel connection, each branch receives the full voltage. Therefore, Bulb P in circuit (4) will have the highest voltage across it compared to the other options (where bulbs are in series or have fewer batteries), resulting in the most current and thus the brightest illumination.

Question 27

Ming conducted an experiment to find out how temperature of liquid B affects its rate of evaporation. He placed beakers 1 and 2, each containing 30 ml of liquid B kept at different temperatures in the same room. He measured the volume of liquid B remaining in each beaker after some time. His results are shown below.
Ming repeated the experiment to find out how exposed surface area of liquid B affects its rate of evaporation. He placed beakers 3 and 4, each containing 30 ml of liquid B with different exposed surface areas in the same room. His results are shown below.
What are the possible values of W and X?

Accepted Answer

(3) W: 90, X: 10. To find W (effect of temperature): Compare Beakers 1 and 2. Exposed surface area is constant. Beaker 2 has less liquid remaining (10 ml vs 20 ml), meaning more evaporated. A higher temperature leads to more evaporation. Thus, W must be higher than 70°C. Only 90°C fits from the options.
To find X (effect of surface area): Compare Beakers 3 and 4. Temperature is constant. Beaker 4 has more liquid remaining (28 ml vs 18 ml), meaning less evaporated. A smaller exposed surface area leads to less evaporation. Thus, X must be smaller than 35 cm². Only 10 cm² fits from the options.
Therefore, W = 90 and X = 10.

Question 28

Ming wants to find out how wind speed affects the volume of liquid B remaining.
Which two beakers should Ming use to conduct a fair test?

Accepted Answer

(1) 1 and 3. To conduct a fair test on how wind speed affects evaporation, all other variables must be kept constant. These constant variables should include the initial volume of liquid, exposed surface area, and temperature. From the provided tables, Beaker 1 and Beaker 3 both have an exposed surface area of 35 cm² and a temperature of 70°C. Thus, they are suitable for comparison when only wind speed is varied.

Question 29

David wanted to investigate whether four rods, E, F, G and H, were electrical conductors or insulators. He used the circuit shown below.
The table below shows what happened when the switch was closed and certain rod(s) was/were removed.
Which of the following conclusions about the rods, A, B, C and D is correct?

Accepted Answer

(4) E: conductor, F: insulator, G: conductor, H: insulator. The question describes testing the conductivity of rods E, F, G, H using a series circuit. A bulb lights up if the circuit is complete and all components are conductors. Based on the conclusion in option (4):
E is an electrical conductor.
F is an electrical insulator.
G is an electrical conductor.
H is an electrical insulator.
This set of properties defines whether the rods allow electricity to pass through them or not.

Question 30

Bulbs A, B, C and D were connected in a circuit hidden in a wooden box as shown. All the light bulbs lit up when the circuit was closed.
Jane removed one light bulb from the circuit each time and observed what happened to the rest of the light bulbs. Her observations are recorded in the table below.
Which of the following correctly shows the circuit hidden in the wooden box?

Accepted Answer

(3). Observation: 'Bulb B removed, None lit.' This is a critical observation as it indicates that bulb B is connected in series with the battery and the rest of the circuit. If B is removed, the circuit is broken, and no other bulbs can light up. Diagram (3) shows bulb B connected in series with the battery. The rest of the bulbs (A, C, and D) are connected in a combination of series and parallel, with the series connection of A and C being parallel to bulb D, and this entire parallel section being in series with bulb B. This arrangement satisfies the condition that removing B causes all other bulbs to go out. While other observations might seem to contradict this diagram depending on interpretation, this key observation is uniquely satisfied.

P5 Science SA2 2025 — Nan Hua

Related papers