Question 1

The diagram shows a mimosa plant. When the mimosa plant is touched, its leaves close up. What does this observation tell you about the mimosa plant?

Accepted Answer

C. It can respond to changes.. The leaves closing up in response to being touched demonstrates the characteristic of living things to respond to changes (stimuli) in their environment.

Question 2

Study the diagram below. Which of the following has been classified wrongly?

Accepted Answer

B. yeast. Yeast is a living thing (a type of fungus) but it has been classified under Non-living. Lion and mushroom are correctly classified as Living, and storybook as Non-living.

Question 3

Swee Lian classified the following items into two groups as shown below. Group A: eraser, fish tank, leather bag. Group B: key, iron nail, gold ring. How were the items grouped?

Accepted Answer

B. A: non-metal, B: metal. Group A items (eraser, fish tank, leather bag) are all made of non-metals. Group B items (key, iron nail, gold ring) are all made of metals. Option C is incorrect because not all metals (e.g., gold) are magnetic.

Question 4

Russell put two grasshoppers and a dish of water into a container. He then covered it with a lid that had tiny holes as shown below. After a week, the grasshoppers died. What could Russell have done so that the grasshoppers would stay alive?

Accepted Answer

C. Put some grass into the container.. Living things need air, food and water. The set-up provided air (through tiny holes) and water but no food. Adding grass would provide food for the grasshoppers to survive.

Question 5

The diagram below shows a plant. Which statement(s) is/are correct? A: The plant has fruits. B: The plant has a weak stem. C: The plant is a flowering plant.

Accepted Answer

A. B only. The plant is shown climbing/leaning on a wooden pole, indicating it has a weak stem and needs support. No fruits are shown in the diagram so A cannot be confirmed, and there is no flower shown to confirm it is a flowering plant.

Question 6

Which of the following is a flowering plant?

Accepted Answer

C. papaya tree. Papaya tree is a flowering plant that reproduces through seeds in its fruits. Bread mould and bracket fungi are fungi, not plants. Bird's nest fern is a non-flowering plant that reproduces by spores.

Question 7

Gopal found living thing X in his garden. Which observations confirm that living thing X is an insect? A: It has wings. B: It has feelers. C: It has six legs. D: It has three body parts.

Accepted Answer

B. C and D only. The defining characteristics of an insect are having six legs and three body parts (head, thorax, abdomen). Having wings and feelers are common to insects but not unique defining features (some non-insects have wings/feelers, and some insects do not have wings).

Question 8

Steffi made the following observations of the characteristics of an adult animal. A: It produces milk. B: It has no feathers. C: It gives birth to its young alive. What is another characteristic that she will observe about the animal?

Accepted Answer

C. It has hair as its outer covering.. An animal that produces milk and gives birth to live young is a mammal. Mammals have hair (or fur) as their outer covering. Gills, scales and moist skin are characteristics of fish/reptiles/amphibians, not mammals.

Question 9

What is a common characteristic of amphibians and birds?

Accepted Answer

C. They reproduce by laying eggs.. Both amphibians and birds reproduce by laying eggs. Amphibians do not have wings, do not always have two legs, and have moist skin (different body covering from birds' feathers).

Question 10

Which of the following about fungi is not correct?

Accepted Answer

B. Fungi are non-flowering plants.. Fungi are NOT plants. They form their own kingdom and are classified separately from plants. The other three statements about fungi are all correct.

Question 11

Three pupils made the following statements about bacteria. Ann: Bacteria are microorganisms. Ben: Bacteria can make its own food. Clara: Bacteria can grow on our food and spoil it. Which pupils were correct?

Accepted Answer

B. Ann and Clara only. Ann is correct - bacteria are microorganisms. Clara is correct - bacteria can grow on food and spoil it. Ben is wrong - most bacteria cannot make their own food.

Question 12

Nur wanted to find out if water is needed for mould to grow. She prepared four set-ups as shown below. Ten drops of water were added to the cakes in set-ups B, C and D. Which two set-ups should she use to conduct the test?

Accepted Answer

B. A and D. To test if water is needed for mould to grow, only water should differ between the two set-ups. Set-ups A (no water, cupboard) and D (has water, cupboard) differ only in the presence of water - all other variables are kept the same.

Question 13

The diagram below shows a plant. Which part of the plant holds it upright to receive sunlight?

Accepted Answer

C. C. The stem (labelled C) holds the plant upright so that leaves can receive sunlight. A is the leaves, B is the fruit, and D is the roots.

Question 14

The diagram below shows two plants, P and Q. Plant Q has more roots than plant P. Thus, roots of plant Q can ____.

Accepted Answer

D. anchor the plant more firmly to the ground. More roots means the plant is more firmly anchored to the ground. Roots do not trap sunlight (leaves do); the stem holds the plant upright; the stem (not roots) carries water to all parts of the plant.

Question 15

May Ling set up an experiment using the two potted plants, Y and Z, as shown below. She placed the plants in the garden and watered them with 50 ml of water daily. She observed the plants for two weeks. May Ling was trying to find out if the ____ affects the growth of a plant.

Accepted Answer

C. number of leaves. Plant Y has more leaves than Plant Z (the variable being changed), while pot size, amount of water (50 ml daily for both), and amount of sunlight (both placed in the garden) are kept the same.

Question 16

Ken placed a packet of tea into a mug as shown. What property of the plastic makes it suitable to be able to fit into the mug?

Accepted Answer

B. It is flexible.. The plastic packet needs to be flexible so it can bend and change shape to fit into the mug.

Question 17

The diagram below shows a food container that can be used to store food. The table below shows the properties of materials, A, B, C and D. A tick (✓) shows that the material has the properties. Which material is most suitable for making the food container?

Accepted Answer

A. A (strong ✓, waterproof ✓). A food container needs to be strong (to hold food without breaking) and waterproof (to contain liquids/moisture). Material A has both required properties.

Question 18

Muthu dipped four strips of different materials, G, H, J and K, into a container of coloured water as shown below. After ten minutes, he took the four strips out of the container. The table below shows his observations. Material G: 0 cm, H: 12 cm, J: 3 cm, K: 7 cm. Which material is most suitable for making a raincoat?

Accepted Answer

A. G. A raincoat must be waterproof to prevent water from passing through. Material G allowed the coloured water to travel 0 cm, meaning water did not pass through it - the most waterproof material.

Question 19

In which direction will a freely suspended bar magnet point to when it comes to a rest?

Accepted Answer

D. north-south. A freely suspended bar magnet always aligns itself in the north-south direction because Earth itself behaves as a giant magnet.

Question 20

The diagram below shows a horseshoe magnet. At which point, A, B, C or D, would the magnet attract the most number of steel pins when brought near a tray of pins?

Accepted Answer

D. D. The poles of a magnet are the strongest points. On a horseshoe magnet, the poles are at the two open ends. Point D is at one of the ends (a pole), while A, B and C are along the sides or curved part of the magnet.

Question 21

Three similar rings made of unknown materials are slotted through a wooden stand as shown below. Which of the following best describes the above observations?

Accepted Answer

B. K and L are magnets.. Rings K and L float apart from each other (showing repulsion), which means they are both magnets with like poles facing each other. J sits on top of K and could be a magnet attracted to K or a magnetic material. The best description given the floating arrangement is that K and L are magnets.

Question 22

Four bar magnets can be arranged as shown below. Which arrangement of the magnets is possible?

Accepted Answer

A. Arrangement with A on top of B, beside E and F. From the original arrangement, ends of bar magnets that touch must have unlike (opposite) poles - they attract. Following this rule consistently through the original arrangement, option (1) shows an arrangement that maintains the correct pole pairings allowed.

Question 23

Ephraim made an electromagnet using a battery and some wires as shown below. He then placed some thumbtacks near the electromagnet but noticed that no thumbtacks were attracted to it. Which could be the reason why no thumbtacks were attracted to the electromagnet? A: The battery was too weak. B: The nail was made of steel. C: The thumbtacks were made of copper.

Accepted Answer

C. A and C only. A weak battery (A) would not produce enough current for the electromagnet to work. Copper is non-magnetic (C), so copper thumbtacks would not be attracted. B is wrong because steel is a magnetic material and is suitable for making an electromagnet's core.

Question 24

Elisha wrote a statement: "When the number of coils of wire around the iron bar increases, the strength of the electromagnet will change." He drew four diagrams, A, B, C and D, as shown below. Which set-ups support his statement?

Accepted Answer

C. B and D. To test the effect of the number of coils on electromagnet strength, only the number of coils should differ - the number of batteries must be kept the same. Set-up B has 10 coils with 3 batteries; Set-up D has 20 coils with 3 batteries. Only the number of coils differs (B vs D), so they form a fair test.

P3 Science SA2 2020 — Catholic High

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