Primary 4 Science Semestral Assessment 2 (End of Year) Paper 3

TuitionGoWhere Practice Paper - Science Primary 4

Answer Key — Version 3 of 5

Subject: Science | Level: Primary 4 | Paper: SA2 Practice Paper | Total Marks: 60

Section A: Multiple Choice Questions (20 marks)

Marking note: 1 mark each. No partial credit.

1. (C) — A mushroom is a living thing (a fungus). Rocks, wooden chairs, and plastic bottles are non-living.

2. (B) — All living things can grow. Not all living things can fly, have legs, or live on land (e.g., fish live in water).

3. (B) — Fish have scales and fins. Dolphins breathe through lungs, give birth to live young, and are warm-blooded — these are mammalian traits.

4. (C) — A bat is a mammal. Crocodiles and lizards are reptiles; penguins are birds.

5. (C) — Birds do not have teeth; they have beaks. Feathers, laying eggs, and having wings are all bird characteristics.

6. (B) — Spiders have 8 legs; insects have 6 legs. Spiders also lack antennae and wings.

7. (B) — Ferns are non-flowering plants (they reproduce via spores). Roses, sunflowers, and orchids are flowering plants.

8. (B) — Reptiles have dry, scaly skin. Moist skin is a characteristic of amphibians; feathers belong to birds; some reptiles give birth to live young but not all.

9. (D) — Frogs are vertebrates (amphibians) and have a backbone. Insects, jellyfish, and earthworms are invertebrates.

10. (C) — A snail is an invertebrate (a mollusc). Sharks, eagles, and snakes are all vertebrates.

Section B: Short Answer Questions (25 marks)

11. [2 marks] — Award 1 mark for each valid difference (maximum 2).

    Acceptable answers (any two):

    • Living things can grow; non-living things cannot.
    • Living things can reproduce; non-living things cannot.
    • Living things need food/water/air; non-living things do not.
    • Living things can respond to changes; non-living things do not.
    • Living things can move (at least some part); non-living things cannot move on their own.
    • Living things carry out respiration; non-living things do not.

    Common mistake: Saying "living things can move" without qualification — plants are living but do not move from place to place. Accept if the student clarifies "move in some way" or gives a valid example.

12. (a) [2 marks] — Organism C.

    • 1 mark for identifying Organism C.
    • 1 mark for explanation: It has scales and no legs, which are characteristics of fish. Fish have scales for protection and use fins (not legs) to swim.

    (b) [2 marks] — Organism B.

    • 1 mark for identifying Organism B.
    • 1 mark for explanation: It has legs and wings but no scales. Birds have legs (with scaly skin on legs), wings, and feathers (not scales on body).

    Marking note: Accept Organism D for bird if the student explains it has legs but no scales (some students may associate "no scales" with feathers). Award 1 mark for the identification and 1 mark for a reasonable explanation.

13. [4 marks] — 1 mark for each correct blank.

    Group	Body covering	Breathes through	Lays eggs?
    Mammal	Fur / hair	Lungs	No*
    Bird	Feathers	Lungs	Yes
    Reptile	Scales	Lungs	Yes
    Amphibian	Moist skin	Lungs & skin	Yes
    Fish	Scales	Gills	Yes

    Common mistakes:

    • Writing "skin" instead of "moist skin" for amphibians — accept "skin" as it is technically correct but "moist skin" is the expected answer.
    • Writing "fins" for fish body covering — incorrect; fins are for movement, scales are the body covering.

14. (a) [1 mark] — Insect (or Insecta).

    (b) [1 mark] — Arachnid (or spider group).

    (c) [1 mark] — Any one valid difference:

    • Insects have 6 legs; arachnids have 8 legs.
    • Insects have 3 body segments; arachnids have 2 body segments.
    • Insects have antennae; arachnids do not.
    • Insects may have wings; arachnids do not have wings.

15. (a) [1 mark] — Invertebrate.

    (b) [1 mark] — Accept any reasonable invertebrate with a soft body that moves slowly:

    • Snail
    • Slug
    • Earthworm
    • Caterpillar
    • Flatworm

    Common mistake: Saying "worm" without specifying — accept as correct.

16. [2 marks] — Award 1 mark for each valid reason (maximum 2).

    Acceptable answers (any two):

    • Whales breathe through lungs (fish use gills).
    • Whales give birth to live young (most fish lay eggs).
    • Whales produce milk to feed their young (fish do not).
    • Whales are warm-blooded (most fish are cold-blooded).
    • Whales have a layer of fat/blubber (fish do not have this in the same way).

    Common mistake: Saying "whales live in water so they are fish" — this is incorrect. Living in water does not determine classification.

17. [2 marks] — Award 1 mark for each valid difference (maximum 2).

    Acceptable answers (any two):

    • Flowering plants produce flowers; non-flowering plants do not.
    • Flowering plants reproduce through seeds (in fruits); non-flowering plants reproduce through spores.
    • Flowering plants have true roots, stems, and leaves; some non-flowering plants (like mosses) do not have true roots/stems/leaves.
    • Examples of flowering plants include roses and sunflowers; examples of non-flowering plants include ferns and mosses.

Section C: Structured / Application Questions (15 marks)

18. (a) [4 marks] — 1 mark each.

    (i) Amphibian — Has backbone → no feathers → no dry, scaly skin → has moist skin → Amphibian.

    (ii) Insect → Invertebrate → has 6 legs → Insect.

    (iii) Fish — Has backbone → no feathers → no dry, scaly skin → no moist skin → has scales & fins → Fish.

    (iv) Arachnid → Invertebrate → does not have 6 legs → has 8 legs → Arachnid.

    (b) [1 mark] — Amphibian.

    Reasoning: The animal has a backbone (so it is a vertebrate), has moist skin, and lays eggs in water — these are all characteristics of amphibians.

19. (a) [1 mark] — 8 different types of organisms.

    (b) [1 mark] — Ant (25 found, the highest number).

    (c) [4 marks] — Award 1 mark for each correctly classified organism. All 8 must be placed correctly for full marks.

    Vertebrates	Invertebrates
    Sparrow	Ant
    Lizard	Earthworm
    Frog	Grasshopper
    	Snail
    	Butterfly

    Common mistakes:

    • Classifying butterfly as a vertebrate — butterflies are insects (invertebrates).
    • Classifying frog as an invertebrate — frogs are amphibians (vertebrates).
    • Missing organisms or listing fewer than 8.

    Marking note: If a student lists 3 vertebrates correctly and 5 invertebrates correctly, award 4 marks. Deduct 1 mark for each misclassified organism, minimum 0.

    (d) [2 marks] — Award up to 2 marks for a valid interpretation.

    Acceptable answers (any two points):

    • There is a wide variety/diversity of organisms in the garden.
    • There are more invertebrates than vertebrates in the garden.
    • Insects (ant, grasshopper, butterfly) are the most common group.
    • The garden has organisms from different groups (insects, molluscs, annelids, birds, reptiles, amphibians).
    • Vertebrates are fewer in number compared to invertebrates.

    Marking note: Award 1 mark for a basic observation (e.g., "there are many different organisms") and 2 marks for a more detailed or comparative observation.

20. (a) [2 marks] — Award 1 mark for each abiotic factor (maximum 2).

    Acceptable answers:

    • Sunlight (mentioned as being blocked by the canopy)
    • Water / moisture / damp conditions
    • Temperature (implied by "tropical")
    • Soil (implied by forest floor)

    Note: "Damp" or "moisture" is acceptable as an abiotic factor related to water availability.

    (b) [2 marks] — 1 mark for each pair correctly identified.

    Vertebrates: Hornbill (bird), frog (amphibian), snake (reptile) — any two.

    Invertebrates: Beetle (insect), ant (insect) — any two.

    Common mistake: Listing "trees" or "ferns" as animals — these are plants, not vertebrates or invertebrates.

    (c) [2 marks] — Award 2 marks for a complete explanation.

    Expected answer: Ferns and mosses are found on the forest floor because they thrive in damp, shady conditions with less sunlight. The canopy blocks most sunlight from reaching the forest floor, creating a shady environment. Ferns and mosses are adapted to grow in low-light, moist conditions, unlike tall trees that need more sunlight and grow above the canopy.

    Marking breakdown:

    • 1 mark for mentioning that the forest floor is shady/damp.
    • 1 mark for linking this to the adaptation of ferns and mosses (they grow well in shade/moisture).

    Common mistake: Saying "ferns are too short to reach the canopy" — this is not the correct biological reason. The correct reason relates to their adaptation to low-light conditions.

END OF ANSWER KEY