Question 1

Which one of the following is a living thing?

Accepted Answer

(3). Living things possess characteristics such as growth, reproduction, respiration, and movement. Among the options, a tiger is the only living organism. The electric fan, airplane, and shopping cart are non-living things.

Question 2

Study the classification chart below. Based on the classification chart above, in which of the groups, A, B, C or D, would you place the following in?

Accepted Answer

(2) B. A mosquito has six legs and two wings. According to the classification chart: Animals -> Has six legs -> Has two wings. This path leads to Group B.

Question 3

Study the diagram below. The roots help the plant to

Accepted Answer

(3) absorb water. Plant roots are primarily responsible for absorbing water and dissolved minerals from the soil, as well as anchoring the plant. Making food (photosynthesis) occurs in the leaves, growing upright is a function of the stem, and absorbing sunlight is done by the leaves.

Question 4

Which organ system is shown in the diagram below?

Accepted Answer

(1) Skeletal system. The diagram clearly depicts the framework of bones that makes up the human skeleton, which is the primary component of the skeletal system.

Question 5

The diagram below shows the growth of a young plant with two missing stages A and B. Which one of the following shows the correct stages for A and B?

Accepted Answer

(3). Plant growth starts from a seed. Stage A should represent the initial germination where a radicle (root) begins to emerge from the seed. Stage B should represent the development of a young seedling with more visible roots, a stem, and initial leaves. Option (3) correctly illustrates this sequence of germination and early growth.

Question 6

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

Accepted Answer

(2). Magnets repel each other when like poles (North-North or South-South) face each other. In option (2), the North pole of the left magnet is facing the North pole of the right magnet, causing them to push each other away.

Question 7

The diagram below shows an umbrella. Plastic is used to make the canopy of the umbrella because plastic

Accepted Answer

(2) is waterproof. The primary function of an umbrella canopy is to protect from rain. For this, the material must be waterproof to prevent water from passing through. While plastic might be non-magnetic or able to float, these properties are not essential for an umbrella canopy's function. It is generally designed to be durable, not break easily.

Question 8

Look at the picture below. Which one of the following explains why Ming Le can see the drawing on the wall?

Accepted Answer

(1). For a non-luminous object (like the drawing on the wall) to be seen, light from a source (the lamp) must first hit the object and then reflect off the object into the observer's eye. Option (1) correctly illustrates this path: light rays go from the lamp to the wall, and then from the wall to Ming Le's eye.

Question 9

John wants to measure the temperature of hot water in a beaker. Which one of the following diagrams shows the correct position of the thermometer when taking the temperature of the water?

Accepted Answer

(2). When measuring the temperature of a liquid, the thermometer bulb must be fully immersed in the liquid but should not touch the bottom or sides of the container. Touching the container could lead to inaccurate readings as it would measure the temperature of the container, not the liquid. Option (2) shows the thermometer correctly positioned in the middle of the water.

Question 10

Which one of the following properties is correct for both air and water?

Accepted Answer

(1) They have mass.. Both air (a gas) and water (a liquid) are forms of matter, and all matter has mass. Water can be seen, but air is invisible. Neither air nor water has a fixed shape; they take the shape of their container. Water (liquid) has a fixed volume, but air (gas) does not, as gases expand to fill their container.

Question 11

The classification chart below shows how some living things are classified. Which of the following correctly represents the headings A, B, C and D?

Accepted Answer

(2) A: Bacteria, B: Ferns, C: Animals, D: Fungi. Based on the characteristics: 
A: 'can only be seen under a microscope' best describes Bacteria. 
B: 'makes its own food' best describes producers like plants (Ferns are non-flowering plants that make their own food). 
C: 'can move freely from place to place' best describes Animals. 
D: 'feeds on dead or living things' best describes consumers or decomposers like Fungi (since Animals is already C). 
Therefore, option (2) is the correct match.

Question 12

Tanya wanted to conduct an experiment to find out if plants needed sunlight to grow well. She prepared two set-ups, X and Y, each with a similar potted plant placed in a clear glass container as shown below. Which of the following conditions must she keep the same in order to conduct a fair test?
A type of soil
B amount of water used to water the plants
C both plants to be placed near an open window

Accepted Answer

(1) A and B only. For a fair test on the effect of sunlight, all other variables must be kept constant (controlled variables). These include the type of soil (A) and the amount of water used (B). If both plants were placed near an open window (C), both would receive sunlight, thus failing to isolate sunlight as the independent variable. To test the effect of sunlight, one plant should receive sunlight, and the other should not, while A and B are kept the same.

Question 13

Osman found living thing Y at a park and made some observations about it for 2 weeks. He recorded his observations below. Which one of the following groups of animals does Y most likely belong to?
* has gills
* feeds on insects
* lays egg in water
* has scales on its body

Accepted Answer

(2) Fish. The characteristics 'has gills', 'lays egg in water', and 'has scales on its body' are all typical features of fish. While some insects feed on insects and amphibians lay eggs in water, the combination of gills and scales strongly indicates that living thing Y is a fish.

Question 14

Jiahao conducted an experiment to find out what conditions would affect the growth of mould. He placed a piece of half-cut juicy apple in each of the three identical sealed containers, P, Q and R. Containers P and Q were placed in a room with a temperature of 30°C. Container R was placed in the freezer with a temperature of 0°C. The conditions of the set-ups are shown in the table below. In which set-ups would Jiahao most likely observe mould growing on the apple after 1 week?

Accepted Answer

(1) P and Q only. Mould requires warmth, moisture, and food to grow. 
- Container P provides 30°C (warmth), has water (moisture), and an apple (food). These are ideal conditions for mould. 
- Container Q provides 30°C (warmth) and an apple (food, which also contains moisture). While no explicit water is added, the apple's moisture and sealed container provide enough humidity. Mould is likely to grow. 
- Container R is at 0°C (cold), which significantly inhibits mould growth, even with food and some moisture. 
Therefore, mould is most likely to grow in containers P and Q.

Question 15

Beng Huat conducted an experiment using two similar plants, X and Y, and placed them in identical containers as shown below. Both containers were filled with the same amount of water at the start of the experiment. He measured the amount of water in the containers after one week and recorded the results in the table shown below. Based only on the results above, what could Beng Huat conclude from his experiment?

Accepted Answer

(2) Plant with less roots takes in less water for the plant.. The experiment measures the amount of water absorbed by the plants. 
- Plant X (with more roots) absorbed 500 ml - 110 ml = 390 ml of water. 
- Plant Y (with less roots) absorbed 500 ml - 300 ml = 200 ml of water. 
Comparing these values, Plant Y (with less roots) absorbed less water (200 ml) than Plant X (390 ml). Therefore, the conclusion is that plants with less roots take in less water. Options (1), (3), and (4) cannot be concluded solely from this experiment's data on water absorption.

Question 16

Study the diagram of the human organ systems below. Danish made the statements below. Which of the following statements above are wrong?
A All the systems need to work together in order for us to live.
B System F directly protects our organs such as the heart.
C Systems G and H work together to take in and remove air from our body.
D Systems E and G work together so that digested food can be transported to other parts of the body.

Accepted Answer

(2) B and C only. Let's identify the systems: E is Circulatory, F is Skeletal, G is Digestive, H is Respiratory. 
- A: All body systems work together. (Correct) 
- B: System F (Skeletal system) provides protection (e.g., rib cage protects the heart). (Correct) 
- C: System G (Digestive) and System H (Respiratory). The respiratory system (H) takes in and removes air, but the digestive system (G) does not. So, this statement is wrong. 
- D: System E (Circulatory) transports digested food (nutrients) absorbed by System G (Digestive) to the body. (Correct) 
Therefore, only statement C is wrong. Since 'C only' is not an option, and option (2) 'B and C only' is the closest with C being definitely wrong, while B is correct. This indicates a potential flaw in the options provided for the question.

Question 17

Study the flowchart about the digestive system below. Which of the following best represents A, B, C and D of the digestive system?

Accepted Answer

(1) A: Small intestine, B: Large intestine, C: Gullet, D: Stomach.. Let's trace the flowchart based on known digestive system functions: 
- 'Mouth' is where digestion occurs and saliva is produced. 
- 'Does digestion take place here? Yes' and 'Is saliva produced here? No' leads to A. This fits the Stomach. 
- 'Does digestion take place here? No' and 'Is water absorbed here? Yes' leads to B. This fits the Large intestine. 
- 'Does digestion take place here? No' and 'Is water absorbed here? No' leads to C. This fits the Gullet (esophagus), which is a passage. 
- From A (Stomach), 'Is digestion completed here? Yes' leads to D. This fits the Small intestine, where most digestion and absorption are completed. 
So, the correct mapping is A: Stomach, B: Large intestine, C: Gullet, D: Small intestine. 
Checking the options, Option (1) has B: Large intestine and C: Gullet correctly matched. It incorrectly assigns A and D. Options (2), (3), (4) do not provide a better fit, with Option (3) being entirely incorrect. Option (1) is the best choice among the given options by having the most correct assignments.

Question 18

The diagram below shows the life cycle of an animal. Which one of the following animals has a similar life cycle to the above?

Accepted Answer

(2) Butterfly. The diagram shows a life cycle with four distinct stages: egg, larva, pupa, and adult. This is characteristic of complete metamorphosis. Among the given animals, a butterfly undergoes complete metamorphosis. Frogs undergo metamorphosis (egg, tadpole, adult) but lack a pupa stage. Cockroaches and grasshoppers undergo incomplete metamorphosis (egg, nymph, adult), which does not include a larva or pupa stage.

Question 19

The table below shows the characteristics of an animal. A tick (✔) shows that the animal has that characteristic. Which of the following could be Animals A and B?

Accepted Answer

(2) Animal A: frog, Animal B: cockroach. Let's analyze the characteristics: 
- Animal A: 'Has three stages in its life cycle' (e.g., egg, tadpole, adult for frog) AND 'Adult lives on both land and in water' (e.g., frog). A frog fits these descriptions well (egg, tadpole, adult are 3 stages, and adult frogs live in both habitats). 
- Animal B: 'Moults several times as it grows'. This is characteristic of insects that undergo incomplete metamorphosis (nymph stage) like a cockroach, or complete metamorphosis (larval stage) like a beetle, or spiders. 
Comparing with options: 
- Option (2) suggests Animal A is a frog and Animal B is a cockroach. A frog fits Animal A's characteristics. A cockroach (nymphs moult) fits Animal B's characteristics. This is the best fit.

Question 20

The set-up below shows sheets E, F and G. The three sheets are arranged in a straight row. All three sheets are of the same thickness and made of different materials. Sheet G has a triangular cut-out as shown in the diagram below. When the torchlight was switched on, light was shone through the hole and a bright triangular shaped light patch was formed on sheet E. Based on the above observation, which of the following sheet(s) do(es) not allow light to pass through?

Accepted Answer

(3) E and G only. For a bright triangular light patch to be formed on sheet E, light must have passed through the triangular cut-out in G, then passed through sheet F, and finally hit sheet E. 
- Sheet E acts as a screen, which means it must block light to display the patch. So E does not allow light to pass through. 
- Since light passed through F to reach E, sheet F must allow light to pass through (it is transparent or translucent). 
- Sheet G creates the triangular shape of the light patch via its cut-out. This implies the material of G itself blocks light (is opaque) and only lets light through the hole. So G does not allow light to pass through. 
Therefore, sheets E and G do not allow light to pass through.

Question 21

The diagram below shows how a shadow of the ball was being cast on the wall. The ball was shifted to four different positions, A, B, C and D. The size of the shadow cast was measured each time and recorded in the table below. At which position was the ball nearest to the wall?

Accepted Answer

(1) A. For an object to cast a shadow, light rays from the source are blocked by the object. The closer an object is to the screen (wall), the smaller and sharper its shadow appears. Conversely, the closer the object is to the light source, the larger its shadow. The question asks for the position where the ball was nearest to the wall, which would result in the smallest shadow. From the table, position A has the smallest shadow height (3 cm).

Question 22

John placed a cup of cold water at 10°C in a room at 25°C for 4 hours. Which of the following graphs correctly shows the change in temperature of the water over the 4 hours?

Accepted Answer

(3). The water starts at 10°C and is in a room at 25°C. Heat will transfer from the warmer room to the colder water, causing the water's temperature to increase until it reaches thermal equilibrium with the room temperature (25°C). The graph should start at 10°C, show an increase in temperature, and then level off as it approaches 25°C. Option (3) correctly depicts this, starting at 10°C and asymptotically approaching 25°C.

Question 23

The diagram below shows some ice cubes in a cup of hot water. If the cup was placed in an air-conditioned room, which one of the following statements is wrong?

Accepted Answer

(2) The hot water loses heat to the ice cubes only.. Let's analyze each statement: 
(1) Ice cubes are colder than hot water, so they will gain heat from the hot water. (Correct) 
(2) The hot water loses heat to the colder ice cubes. However, since the cup is in an air-conditioned room (which is cooler than the hot water), the hot water will also lose heat to the surrounding air. Therefore, stating it loses heat 'to the ice cubes only' is wrong. (Incorrect statement) 
(3) Ice (melting point 0°C) is at a lower temperature than hot water (above 0°C). (Correct) 
(4) A thermometer is the appropriate instrument to measure temperature. (Correct) 
Thus, statement (2) is wrong.

Question 24

The table below states some characteristics of substance X and Y. Based on the characteristics above, which one of the following statements about substances X and Y is correct?

Accepted Answer

(3) Substance X is most likely a solid while substance Y is a gas.. Based on the table: 
- Substance X: 'Does not take the shape of the container' (meaning it has its own fixed shape) and 'Cannot be compressed'. These are defining characteristics of a solid. 
- Substance Y: 'Takes the shape of the container' and 'Can be compressed'. These are defining characteristics of a gas. 
Let's evaluate the options: 
(1) Only Substance X (solid) has a definite shape. (Incorrect) 
(2) Substance X (solid) has a definite volume, but Substance Y (gas) does not. (Incorrect) 
(3) Substance X is most likely a solid while substance Y is a gas. (Correct) 
(4) Substance X is a solid, not a gas. Substance Y is a gas, not a liquid. (Incorrect)

Question 25

Sally has two beakers, A and B. She transferred all the water and the same metal block from beaker A to beaker B. The diagram below shows the amount of water in each of the beakers. Sally made the following observations: Based on the set-ups, which of the observation(s) made is/are wrong?
A Water has a definite shape.
B Water has a definite volume.
C The metal block has a definite shape.
D The metal block has a definite volume.

Accepted Answer

(1) A only. Let's analyze Sally's observations: 
- A: Water is a liquid and takes the shape of its container, so it does not have a definite shape. This statement is wrong. 
- B: Water (a liquid) has a definite volume. This statement is correct. 
- C: The metal block (a solid) has a definite shape. This statement is correct. 
- D: The metal block (a solid) has a definite volume. This statement is correct. 
Therefore, only observation A is wrong.

Question 26

Miss Chua used material Z to make a part of the objects as shown in the diagram below. Based on your observation, which property/properties of material Z is/are necessary for the use of each object above?
A Flexible
B Waterproof
C Able to float
D Allows most light to pass through

Accepted Answer

(3) B and D only. Material Z is used for a beaker, a spectacle lens, and a fish bowl. 
- A beaker and a fish bowl must be able to hold liquids without leaking, so the material must be Waterproof (B). 
- A spectacle lens, beaker, and fish bowl must all allow vision through them, so the material must allow most light to pass through (D), meaning it is transparent or translucent. 
- Flexible (A) is not a necessary property, as these objects are typically rigid. 
- Able to float (C) is not a necessary property for these objects. 
Therefore, properties B (waterproof) and D (allows most light to pass through) are necessary.

Question 27

The end of two objects, A and B were labelled and brought very near to the North pole of a bar magnet as shown in the diagram below. The results of the experiment are recorded in the table below. A tick (✔) shows the observable results. Based on the above results, which of the following statements is correct?

Accepted Answer

(4) End X of object B is the North pole of a magnet.. Let's analyze the interactions: 
- Object A: End T is attracted to the North pole of the bar magnet. This indicates that object A is either a magnetic material or a magnet with a South pole at end T. It does not definitively confirm A is a magnet. 
- Object B: End V is attracted to the North pole, while End X is repelled by the North pole. Repulsion is the conclusive test for magnetism. If End X is repelled by a North pole, then End X must also be a North pole. This confirms that object B is a magnet. 
Evaluating the options: 
(1) A could be a magnetic material, not necessarily a magnet. (Incorrect) 
(2) B is definitively a magnet due to repulsion. (Incorrect) 
(3) If End T were a North pole, it would repel the bar magnet's North pole, not attract it. (Incorrect) 
(4) Since End X of object B is repelled by the North pole of the bar magnet, End X must be a North pole. (Correct)

Question 28

The diagram below shows a compass and four bar magnets that are attracted to one another. Which of the following represents the poles at A, B, C and D correctly?

Accepted Answer

(4) A: south, B: north, C: south, D: north. A compass needle's North pole points towards a magnetic South pole, and its South pole points towards a magnetic North pole. The compass shows its N pole pointing towards D and its S pole pointing towards B. 
- Therefore, the end of magnet D nearest the compass must be a South pole. 
- The end of magnet B nearest the compass must be a North pole. 
Now, consider the attraction between the magnets, where opposite poles attract. The magnets form a loop A-B-C-D-A. 
- If B's inner end is North, and B attracts A, then A's inner end must be South. 
- If B's inner end is North, and B attracts C, then C's inner end must be South. 
- If C's inner end is South, and C attracts D, then D's inner end must be North. This contradicts our deduction that D's inner end is South. 
Given the options and the inherent contradiction in the diagram's interactions (attraction in a loop combined with compass direction), there is no option that is perfectly consistent with all conditions and standard physics. However, if we prioritize the compass readings and the general idea of alternating poles in a ring for attraction: 
- B's inner pole is North. 
- D's inner pole is South. 
This rules out options (1) and (3). 
Now for A and C: if A's inner pole is South and C's inner pole is South, it could satisfy attraction to B's inner North pole. But then C's outer pole (facing D) would be North, which attracts D's inner South pole. A's outer pole (facing D) would be North, which attracts D's inner South pole. 
This leads to A: South, B: North, C: South, D: South. This is option (4) if 'north' and 'south' refer to the inner ends. So option (4) is the most plausible by making B's inner pole N and D's inner pole S, and assuming A and C's inner poles are S. However, the text option (4) for D is North, which again creates a conflict. 
Let's re-evaluate option (2): A: south, B: north, C: north, D: south. 
- Compass check: N points to D (South - consistent). S points to B (North - consistent). 
- Attraction check: A (S) attracted to B (N) - Consistent. B (N) attracted to C (N) - Inconsistent (would repel). C (N) attracted to D (S) - Consistent. D (S) attracted to A (S) - Inconsistent (would repel). 
This question is flawed with inconsistent information. However, if forced to select an option, and going with the provided answer key, it suggests Option (2). Based on strict scientific deduction, no option works without contradiction.

P4 Science CA2 2023 — Nanyang

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