Primary 4 Science Plants Quiz

Primary 4 Science Quiz - Plants: Answer Key

Total Marks: 30

Section A: Multiple-Choice Questions (10 marks)

1. C) Root

• Marks: 1
• Explanation: Roots are the part of the plant that grow underground. Their main job is to absorb water and dissolved minerals from the soil. The stem transports these, the leaf makes food, and the flower is for reproduction.
• Common Mistake: Students might confuse the stem's transport function with the root's absorption function.

2. B) Make food for the plant

• Marks: 1
• Explanation: Leaves contain chlorophyll, which captures sunlight. Using sunlight, water, and carbon dioxide, the leaf performs photosynthesis to make food (sugar) for the plant.
• Common Mistake: Students may think leaves absorb water, but that is the root's job.

3. B) Stem

• Marks: 1
• Explanation: The stem is the part of the plant that grows above ground and connects the roots (in the soil) to the leaves and flowers (above ground). It acts like a highway for water and food.
• Common Mistake: Students might think the roots connect to the leaves directly.

4. C) Transporting water and food between roots and leaves

• Marks: 1
• Explanation: The stem contains tubes (xylem and phloem, though these terms are not required at P4) that carry water and minerals up from the roots to the leaves, and food down from the leaves to the rest of the plant. If the stem is broken, this transport system is disrupted.
• Common Mistake: Students might think the stem's main job is just to hold the plant up, forgetting its transport role.

5. C) Root

• Marks: 1
• Explanation: Roots are the part of the plant that grow downwards into the soil. They are typically not visible above ground.

6. C) To make food

• Marks: 1
• Explanation: Making food is the function of the leaf, not the root. The roots absorb water and minerals and anchor the plant.
• Common Mistake: Students may not clearly separate the functions of different plant parts.

7. C) Leaf

• Marks: 1
• Explanation: Leaves need sunlight to make food through photosynthesis. In a dark cupboard, there is no light, so the leaf cannot perform its function. The roots and stem can still function for a while, but the plant will eventually die.
• Common Mistake: Students might think the roots will be affected first because they can't get water, but the question is about which part has difficulty performing its function.

8. B) Straw

• Marks: 1
• Explanation: A straw is used to suck up a drink. Similarly, the stem acts like a straw, sucking up water and minerals from the roots and transporting them to the leaves.
• Common Mistake: Students might choose "anchor" (root's function) or "factory" (leaf's function).

9. D) Flower

• Marks: 1
• Explanation: The flower is the reproductive part of the plant. It produces seeds, which can grow into new plants.
• Common Mistake: Students might think the leaf or stem is for reproduction.

10. B) It will not be able to make food.

• Marks: 1
• Explanation: Leaves need to take in carbon dioxide from the air and release oxygen and water vapour through tiny holes called stomata. If the leaves are covered in oil, these holes are blocked, so the leaf cannot get the carbon dioxide it needs to make food.
• Common Mistake: Students might think the oil blocks water absorption, but water is absorbed by the roots, not the leaves.

Section B: Fill in the Blanks (10 marks)

11. Root

• Marks: 2
• Explanation: The root is the plant part that grows into the soil and absorbs water and dissolved minerals.

12. Leaf

• Marks: 2
• Explanation: The leaf is the plant's food-making factory. It uses sunlight, water, and carbon dioxide to produce food.

13. Stem

• Marks: 2
• Explanation: The stem supports the plant and contains tubes that transport water and minerals from the roots to the leaves, and food from the leaves to other parts.

14. Flower

• Marks: 2
• Explanation: The flower is often brightly coloured to attract insects for pollination. It is the part of the plant responsible for reproduction.

15. Root

• Marks: 2
• Explanation: Roots anchor the plant firmly in the soil, preventing it from being blown over by the wind or washed away by water.

Section C: Open-Ended Questions (10 marks)

16. Answer: The plant will eventually die because the roots are responsible for absorbing water and minerals from the soil. Without roots, the plant cannot get the water and nutrients it needs to survive. It will also not be anchored in the ground.

• Marks: 2
• Marking Scheme:
  • 1 mark for stating that roots absorb water and minerals.
  • 1 mark for explaining that without them, the plant cannot get what it needs to survive.
• Common Mistake: Students might only say the plant will fall over, forgetting the absorption function.

17. Answer: The leaves turn yellow because they cannot make food. Leaves need sunlight to make food for the plant. In a room with no windows, there is no sunlight, so the leaves cannot perform photosynthesis. The plant uses up its stored food, and the leaves lose their green colour (chlorophyll) and turn yellow.

• Marks: 2
• Marking Scheme:
  • 1 mark for stating that leaves need sunlight to make food.
  • 1 mark for explaining that without sunlight, the leaves cannot make food and turn yellow.
• Common Mistake: Students might say the plant died from lack of water, but the question specifies the leaves turning yellow, which is a sign of lack of light.

18. Answer: (The student should correctly label the diagram)

• Marks: 2
• Marking Scheme:
  • 1 mark for correctly labelling the roots.
  • 1 mark for correctly labelling the stem, leaves, and flower.
• Explanation: This is a direct test of the student's ability to identify and name the main parts of a plant.

19. Answer: No, this is not possible. A plant needs sunlight for its leaves to make food. If the plant is kept in a dark cupboard, the leaves cannot make food. Without food, the plant will not be healthy and its leaves will eventually turn yellow and die. The leaves cannot stay healthy and green without sunlight.

• Marks: 2
• Marking Scheme:
  • 1 mark for stating "No" and giving a correct reason (leaves need sunlight to make food).
  • 1 mark for explaining that without food, the plant cannot be healthy.
• Common Mistake: Students might focus on the watering, thinking that water is enough for the plant to be healthy.

20. Answer: Two differences:

1. The root absorbs water and minerals from the soil, while the stem transports these substances to the leaves.
2. The root anchors the plant in the ground, while the stem supports the leaves and flowers above ground.

• Marks: 2
• Marking Scheme:
  • 1 mark for each correct and clearly stated difference.
• Explanation: Students need to compare the functions of two different plant parts. They should not just list functions but show how they are different.
• Common Mistake: Students might list two functions of the root or two functions of the stem, instead of comparing them.