Primary 4 Science Practice Paper 2

TuitionGoWhere Practice Paper - Science Primary 4 (Answer Key)

Subject: Science
Level: Primary 4
Paper: Practice Paper 2 (Version 2 of 5)
Total Marks: 60

SECTION A: Multiple-Choice Questions (28 marks)

1. Answer: (2) Bacteria, yeast, mould [2]

Explanation:

• Bacteria, yeast, and mould are all micro-organisms (living things).
• Mushroom and moss are living, but rock is non-living.
• Cloud, rain, wind are non-living natural phenomena.
• Robot, computer, car are man-made non-living things.

2. Answer: (1) X: Flowering Plants, Y: Vertebrates [2]

Explanation:
The classification chart shows:

• Living Things → Plants → Flowering and Non-Flowering
• Living Things → Animals → Vertebrates and Invertebrates

X is the sub-group under Plants, so X = Flowering Plants.
Y is the sub-group under Animals, so Y = Vertebrates.

3. Answer: (2) 2 [2]

Explanation:

• Fern: Reproduces by spores ✓
• Mushroom (fungus): Reproduces by spores ✓
• Rose plant (flowering plant): Reproduces by seeds ✗
• Bacterium: Reproduces by binary fission ✗

Total = 2 organisms (fern and mushroom).

4. Answer: (2) Bacteria can only be seen with a microscope. [2]

Explanation:

• (1) False: Many bacteria are beneficial (e.g., in digestion, decomposition, food production).
• (2) True: Bacteria are microscopic single-celled organisms.
• (3) False: Bacteria are not plants; they lack chlorophyll and have different cell wall composition.
• (4) False: Bacteria reproduce asexually by binary fission, not by laying eggs.

5. Answer: (3) C [2]

Explanation:
The leaf (part C) contains chlorophyll and carries out photosynthesis to make food for the plant.

• Roots absorb water and minerals.
• Stem transports water and food.
• Flowers are reproductive structures.
• Fruits protect and disperse seeds.

6. Answer: (2) A and C only [2]

Explanation:
Characteristics of fungi:

• A. They reproduce by spores. ✓ (True)
• B. They make their own food. ✗ (False - they are decomposers, no chlorophyll)
• C. They feed on dead or decaying matter. ✓ (True - they are saprotrophs)
• D. They have chlorophyll. ✗ (False - they lack chlorophyll)

7. Answer: (2) Fungus [2]

Explanation:
Following the flowchart:

1. Does it make its own food? No → Go to next question.
2. Does it reproduce by spores? Yes → Fungus.

The organism matches the path to Fungus.

8. Answer: (2) Frog, lizard, eagle [2]

Explanation:
Vertebrates have a backbone.

• (1) Earthworm, snail, spider → All invertebrates (no backbone).
• (2) Frog (amphibian), lizard (reptile), eagle (bird) → All vertebrates ✓
• (3) Jellyfish, starfish, crab → All invertebrates.
• (4) Butterfly, beetle, grasshopper → All insects (invertebrates).

9. Answer: (2) Pupa [2]

Explanation:
Butterfly life cycle (complete metamorphosis):
Egg → Larva (caterpillar) → Pupa (chrysalis) → Adult butterfly

The stage after larva is pupa.

10. Answer: (2) B and C only [2]

Explanation:
For a fair test comparing white bread vs. wholemeal bread:

• A. Type of bread → This is the changed variable (independent variable), must be different.
• B. Amount of water added → Must be kept same (controlled variable). ✓
• C. Temperature of surroundings → Must be kept same (controlled variable). ✓
• D. Time taken for mould to appear → This is the measured variable (dependent variable), not controlled.

11. Answer: (3) Fern [2]

Explanation:

• Hibiscus, Orchid, Mango tree → Flowering plants (produce flowers and fruits).
• Fern → Non-flowering plant (reproduces by spores, no flowers/fruits).

12. Answer: (3) Y [2]

Explanation:
Mammals are vertebrates (have backbone) and do not make their own food.

• W: Makes own food → Plant.
• X: Reproduces by spores → Fungus.
• Y: No food-making, no spores, has backbone → Animal (vertebrate) → Mammal possible.
• Z: No backbone → Invertebrate.

13. Answer: (2) They can only be seen under a microscope. [2]

Explanation:
Micro-organisms are organisms too small to be seen with the naked eye; they require a microscope. This is the defining characteristic. Bacteria are single-celled and microscopic.

14. Answer: (1) Egg → Larva → Pupa → Adult [2]

Explanation:
Mosquito undergoes complete metamorphosis:
Egg → Larva (wriggler) → Pupa (tumbler) → Adult mosquito

• (2) is incomplete metamorphosis (e.g., grasshopper).
• (3) and (4) have incorrect stage order.

SECTION B: Structured Questions (22 marks)

15. (a) The gills produce and release spores for reproduction. [1]

Marking note: Accept "produce spores" or "release spores" or "for reproduction".

(b) The mushroom is a decomposer (fungus) that feeds on dead/decaying organic matter. The rotting log provides food (nutrients) for the mushroom. [1]

Marking note: Must mention decomposer/fungus feeding on dead matter.

(c) No, a mushroom is not a plant. It is a fungus. It does not have chlorophyll and cannot make its own food (unlike plants). [1]

Marking note: Must state "No" and give a valid reason (no chlorophyll / cannot photosynthesise / is a fungus).

16. [3]

Marking: ½ mark per correct placement (6 organisms × ½ = 3 marks).
Note: Yeast is a fungus (single-celled), not a bacterium. Moss and fern are non-flowering plants. Eagle (bird) and shark (fish) are vertebrates/animals.

17. (a) Birds [1]

Explanation: Birds have feathers and lay eggs.

(b) Amphibians [1]

Explanation: Amphibians (e.g., frog) breathe through gills as young (tadpole) and lungs as adult; they have moist skin.

(c) Mammals give birth to live young (live birth), while reptiles lay eggs. [1]

Marking note: Accept "Mammals: live birth; Reptiles: lay eggs" or equivalent.

18. (a) Tadpole with hind legs / Tadpole with back legs [1]

Explanation: Stage P shows a tadpole that has developed hind legs but not front legs yet.

(b) Any two differences: [2]

1. Tadpole lives in water; adult frog lives on land and in water.
2. Tadpole breathes through gills; adult frog breathes through lungs (and skin).
3. Tadpole has a tail; adult frog has no tail.
4. Tadpole has no legs; adult frog has four legs.
5. Tadpole eats algae/plants; adult frog eats insects (carnivore).

Marking: 1 mark per valid difference.

19. (a) Mould (or mould spores growing into mould) [1]

(b) Mould spores in the air landed on the bread. The bread provided food, and the warm, moist, dark conditions in the sealed bag allowed the spores to germinate and grow into mould. [1]

Marking note: Must mention spores landing + suitable conditions (food, warmth, moisture).

(c) Keep the bread in the refrigerator (low temperature) / Keep the bread dry / Store in an airtight container with no moisture / Add preservatives. [1]

Marking note: Any one valid method to slow mould growth.

20. (a) Plants [1]

Explanation: Organisms that make their own food are plants (photosynthesis).

(b) 1. It does not make its own food (heterotrophic).
2. It reproduces by spores. [2]

Marking: 1 mark per characteristic. These are the two decision criteria leading to Group B.

(c) Insect (e.g., butterfly, beetle, grasshopper) / Spider / Snail / Earthworm / Jellyfish / Any invertebrate animal. [1]

Explanation: Group D = No food-making + No spores + No backbone = Invertebrate animals.

21. (a) P and R [1]

Explanation: Flowering plants bear flowers and fruits, and reproduce by seeds (not spores).

(b) Q and S [1]

Explanation: Non-flowering plants do not bear flowers or fruits; they reproduce by spores.

(c) The fruit protects the seeds and helps in seed dispersal. [1]

Marking note: Accept "protects seeds" or "disperses seeds" or both.

22. (a) Plant cell [1]

(b) Chloroplasts contain chlorophyll and trap light energy for photosynthesis (food-making). [1]

(c) Cell wall / Large vacuole (accept either) [1]

Explanation: Plant cells have cell wall (rigid structure) and large central vacuole; animal cells lack these.

SECTION C: Open-Ended Questions (10 marks)

23. (a) Set-up A and Set-up B [1]

Explanation: Only difference is light (A: light, B: dark). Other variables (water, temperature) are the same.

(b) Mould does not need light to grow. / Light is not necessary for mould growth. [1]

Explanation: Mould grew in both light (A) and dark (B, D), so light is not a required condition.

(c) The temperature in Set-up D (5°C in refrigerator) is too low for mould to grow actively. Mould grows best in warm conditions (around 30°C). Low temperature slows down or stops the metabolic activities of mould. [2]

Marking:

• 1 mark: Identifying low temperature as the reason.
• 1 mark: Explaining that low temperature slows/stops mould growth/metabolism.

24. (a) Any two differences: [2]

1. Young plant has small roots; adult plant has extensive/large root system.
2. Young plant has short/soft stem; adult plant has tall/woody stem.
3. Young plant has few small leaves; adult plant has many large leaves.
4. Young plant has no flowers/fruits; adult plant has flowers and fruits.
5. Young plant is smaller in size; adult plant is larger.

Marking: 1 mark per valid difference.

(b) Two conditions for seed germination: [2]

1. Water (moisture) – to activate enzymes and swell the seed.
2. Air (oxygen) – for respiration to release energy.
3. Suitable/Warm temperature – for enzyme activity.

Marking: 1 mark per condition (any two). "Sunlight" is NOT needed for germination (needed later for photosynthesis).

25. (a) Fungi (or Fungus) [1]

(b) The organism does not make its own food (so it is not a plant), reproduces by spores (characteristic of fungi), feeds on dead/decaying matter (saprotrophic nutrition, typical of fungi), and cannot move (unlike animals). These characteristics match fungi. [2]

Marking:

• 1 mark: Correct group identification in reasoning (not plant, not animal, not bacteria).
• 1 mark: Linking at least two observed characteristics to fungi traits.

(c) It helps in decomposition, breaking down dead organic matter and recycling nutrients back into the environment/soil for plants to use. [1]

Marking note: Accept "decomposer", "recycles nutrients", "breaks down dead matter", "returns nutrients to soil".

END OF ANSWER KEY

Total Marks: 60