Primary 5 Science Life Cycles Quiz

Primary 5 Science Quiz - Life Cycles (Answer Key)

Total Marks: 40

Section A: Multiple-Choice Questions (10 × 1 mark = 10 marks)

1. C — Butterfly undergoes complete metamorphosis with four stages: egg, larva (caterpillar), pupa (chrysalis), and adult. Grasshopper and cockroach undergo incomplete metamorphosis (three stages: egg, nymph, adult). Chicken has a simple life cycle (egg, chick, adult).

2. C — Fertilisation occurs in the flower (Stage C), where the male reproductive cell from the pollen grain fuses with the female reproductive cell in the ovule. Stage A is the seed, Stage B is the seedling, and Stage D is the fruit containing seeds (which develops after fertilisation).

3. C — Grasshopper undergoes incomplete metamorphosis: the young (nymph) resembles the adult but is smaller and wingless, and it moults several times to reach adulthood. Mosquito and beetle undergo complete metamorphosis (with pupa stage). Frog undergoes metamorphosis but the young (tadpole) does not resemble the adult.

4. B — Fertilisation in humans occurs in the fallopian tube (oviduct), where the sperm meets the egg. The ovary produces the egg, the uterus is where the fertilised egg implants and develops, and the vagina is the birth canal.

5. D — The anther (part Z) is the male reproductive part of the flower that produces pollen grains. The stigma (W) receives pollen, the style (X) connects stigma to ovary, and the ovary (Y) contains ovules.

6. B — Seeds dispersed by water (e.g., coconut, water lily) have waterproof coverings or fibrous husks that allow them to float. Not all seeds are wind-dispersed (A is false). Animal-dispersed seeds may have hooks or be fleshy, but not always sweet (C is false). Explosive dispersal occurs in many plants, not just legumes (D is false).

7. C — Sunlight is not necessary for germination. Germination requires water (to activate enzymes), oxygen (for respiration), and suitable temperature. Photosynthesis (which needs sunlight) begins only after the seedling develops leaves.

8. B — Frog undergoes complete metamorphosis with distinct stages: egg, tadpole (larva), froglet, adult. The young (tadpole) looks very different from the adult and lives in a different habitat. Incomplete metamorphosis (A) has young resembling adults. Frogs reproduce sexually (C is false) and need water for reproduction (D is false).

9. A — Chicken: 3 stages (egg, chick, adult). Butterfly: 4 stages (egg, larva/caterpillar, pupa/chrysalis, adult). Option B incorrectly uses "nymph" for butterfly. Option C gives chicken 4 stages and butterfly 3. Option D gives chicken only 2 stages.

10. C — During early germination, the seedling relies on stored food in the cotyledons for respiration to release energy for growth. This uses up the stored food, causing a slight mass decrease. Once the seedling develops leaves and begins photosynthesis, it produces its own food and mass increases. Transpiration (A) causes water loss but not the initial dip. Seed coat falling off (B) contributes negligibly. Radicle growth (D) does not cause mass loss.

Section B: Structured Questions (6 × 3 marks = 18 marks)

11.
(a) Complete metamorphosis [1]
Marking note: Accept "complete metamorphosis" only. "Metamorphosis" alone is insufficient.

(b) The larva (wriggler) moves actively by wriggling, while the pupa (tumbler) moves by tumbling/rolling and is less active. [1]
Marking note: Accept any valid difference in movement: larva swims actively, pupa only moves when disturbed; larva feeds, pupa does not feed.

(c) Mosquitoes lay eggs in stagnant water. The larva and pupa stages are aquatic and need water to survive and develop. Removing stagnant water removes their breeding grounds. [1]
Marking note: Must mention that larval/pupal stages are aquatic and need water.

12.
(a) The wing-like structure increases the surface area of the seed, allowing it to be carried further by the wind / stay airborne longer. [1]
Marking note: Must link wing-like structure to increased air resistance / longer flight time.

(b) The fibrous husk traps air, making the seed buoyant so it can float on water. [1]
Marking note: Accept "fibrous husk allows seed to float" or "traps air for buoyancy".

(c) The hooks catch onto the fur of passing animals. The seeds are carried away from the parent plant and fall off later at a different location. [1]
Marking note: Must mention hooks catch on fur/feathers and seeds are transported.

13.
(a) A (Ovary) [1]
Marking note: The ovary produces egg cells (ova).

(b) B (Fallopian tube) [1]
Marking note: Fertilisation typically occurs in the fallopian tube (oviduct).

(c) The uterus (womb) is where the fertilised egg implants and the baby develops. It provides protection and nutrients (via the placenta) for the developing foetus. [1]
Marking note: Must mention implantation and development/nourishment.

14.
(a) To find out the conditions necessary for seed germination. [1]
Marking note: Accept "To investigate the conditions needed for germination" or similar.

(b) Set-up A and Set-up B [1]
Marking note: A has water (wet cotton wool), B has no water (dry cotton wool). All other conditions (temperature, light) are the same.

(c) The temperature in Set-up C (5°C) is too low for the enzymes in the seed to function properly. Metabolic processes (respiration) needed for germination are too slow or stop at low temperatures. [1]
Marking note: Must link low temperature to enzyme inactivity / slow metabolism.

15.
(a) Fertilisation [1]
Marking note: The process described (pollen tube growing to ovule) is fertilisation. Pollination is transfer of pollen to stigma.

(b) The male reproductive cell from the pollen grain fuses with the female reproductive cell in the ovule to form a zygote. [1]
Marking note: Must mention fusion of male and female reproductive cells / gametes.

(c) The ovule develops into the seed and the ovary develops into the fruit. [1]
Marking note: Both parts required for 1 mark. Order does not matter.

16.
(a) A spore is a single cell and does not contain stored food, while a seed is multicellular and contains stored food (in cotyledons) for the embryo. [1]
Marking note: Accept other valid differences: spore develops into gametophyte first, seed develops directly into sporophyte; spore is microscopic, seed is larger.

(b) The male gametes (sperm) of ferns are flagellated and need to swim through water to reach the female gametes (eggs) on the prothallus. [1]
Marking note: Must mention swimming sperm / flagellated male gametes needing water.

(c) Sporophyte (adult fern) [1]
Marking note: The dominant, visible plant is the sporophyte generation.

Section C: Open-Ended Questions (4 × 3 marks = 12 marks)

17.
(a) Similarities (any two):

• Both start from eggs.
• Both undergo metamorphosis (change in form during life cycle).
• Both have distinct young and adult stages.
• Both reproduce sexually. [1]
  Marking note: Award 1 mark for any two correct similarities.

(b) Differences (any two):

• Butterfly undergoes complete metamorphosis (4 stages: egg, larva, pupa, adult); grasshopper undergoes incomplete metamorphosis (3 stages: egg, nymph, adult).
• Butterfly young (caterpillar) looks very different from adult; grasshopper young (nymph) resembles adult but is smaller and wingless.
• Butterfly has a pupa stage; grasshopper has no pupa stage.
• Butterfly larva has no wings; grasshopper nymph develops wing buds that grow with each moult. [1]
  Marking note: Award 1 mark for any two correct differences.

(c) The pupa stage is when the caterpillar's body undergoes complete transformation (histolysis and histogenesis). Tissues and organs are broken down and rebuilt into adult structures (wings, compound eyes, reproductive organs, etc.). This allows the adult butterfly to have a completely different body form adapted for flight and reproduction. [1]
Marking note: Must explain that pupa stage allows complete restructuring of body / transformation from larval to adult form.

18.
(a) Ovary [1]
Marking note: The ovary develops into the fruit after fertilisation.

(b) Pollination is the transfer of pollen grains from the anther (male part) to the stigma (female part) of a flower. [1]
Marking note: Must mention transfer from anther to stigma. Accept "transfer of pollen from male to female part of flower".

(c) Brightly coloured petals and nectar attract pollinators (insects, birds). When pollinators visit the flower to feed on nectar, pollen grains stick to their bodies and are transferred to the stigma of another flower, bringing about pollination. [1]
Marking note: Must link attraction of pollinators to pollen transfer.

19.
(a) Water, oxygen, and suitable (warm) temperature. [1]
Marking note: All three required for 1 mark. Accept "warmth" for suitable temperature.

(b) The seedling uses the stored food in the cotyledons (seed leaves) for respiration to release energy for growth. The cotyledons shrink as the stored food is used up, until the first true leaves develop and photosynthesis begins. [1]
Marking note: Must mention stored food in cotyledons used for respiration / energy.

(c) Any two:

• Anthers are large and hang outside the flower (exposed) to release pollen easily into the wind.
• Stigma is large, feathery, or branched to catch airborne pollen grains.
• Petals are small or absent (not brightly coloured) since they do not need to attract pollinators.
• Pollen grains are light and smooth to be carried by wind.
• Flowers produce large quantities of pollen to increase chances of pollination. [1]
  Marking note: Award 1 mark for any two correct structural adaptations for wind pollination.

20.
(a) Umbilical cord [1]
Marking note: The umbilical cord connects the foetus to the placenta, which is attached to the uterus wall.

(b) Any two: Oxygen, nutrients (glucose, amino acids, vitamins, minerals), antibodies. [1]
Marking note: Award 1 mark for any two correct substances from mother to baby.

(c) The mother's and baby's blood may have different blood groups. If they mix, the mother's antibodies could attack the baby's red blood cells (or vice versa), causing harm. The placenta acts as a barrier allowing exchange of substances by diffusion without direct blood mixing. [1]
Marking note: Must mention different blood groups / immune reaction risk, and that placenta allows exchange without mixing.

End of Answer Key

Note: This quiz is generated from LLM-inferred templates aligned with the Primary 5 Science syllabus (Cycles in Plants and Animals - Reproduction). It is not derived from past-year examination papers.