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Primary 4 Science Life Cycles Quiz
Free P4 Science Life Cycles quiz, Ox Exam version, with questions, answers, and syllabus-aligned practice for Singapore students.
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Answers
Primary 4 Science Quiz - Life Cycles (Answer Key)
Answer 1.
B. egg → larva → pupa → adult
Answer 2.
C. grasshopper
Answer 3.
A. It lives in water and breathes through gills.
Answer 4.
D. cockroach
Answer 5.
C. They both begin their life cycle as eggs.
Answer 6.
(a) Stage X is the pupa (chrysalis). (b) The caterpillar's body changes completely inside the pupa and becomes an adult butterfly.
Answer 7.
Similarity: Both have six legs, antennae and three body parts. Difference: The nymph has no wings (and cannot fly), while the adult has fully grown wings.
Answer 8.
Many eggs are eaten by predators such as fish, birds and other water animals. Laying many eggs increases the chance that some will survive to become adult frogs.
Answer 9.
(a) The mealworm. (b) The larva has no wings, a soft worm-like body and is long and segmented, unlike the winged adult beetle.
Answer 10.
Three stages: egg → chick → adult chicken.
Answer 11.
(a) Moulting is the shedding of the old outer covering (exoskeleton). (b) The exoskeleton cannot grow, so the nymph must shed it in order to grow bigger.
Answer 12.
Tadpole: It has a tail and gills for swimming and breathing in water. Adult frog: It has strong hind legs for hopping on land and breathes with lungs (and through its skin).
Answer 13.
The adult female mosquito. It bites and sucks blood from humans and can spread diseases such as dengue. The larva and pupa live in water and do not bite people.
Answer 14.
No, Sam is not correct. Some insects, such as the grasshopper, cockroach and dragonfly, have a three-stage life cycle with no pupa stage.
Answer 15.
(a) Both have four stages: egg, larva, pupa and adult. (b) The young (caterpillar/grub) has no wings and crawls, while the adult has wings and can fly.
Answer 16.
Three-stage: egg → nymph → adult; example: grasshopper (or cockroach, dragonfly). Four-stage: egg → larva → pupa → adult.
Answer 17.
Many of the eggs and tadpoles were eaten by predators such as fish, birds and other animals. Some also died because of changes in the pond, so only a few survived to become adult frogs.
Answer 18.
Group 1 (three-stage): grasshopper, cockroach, dragonfly. Group 2 (four-stage): housefly, mosquito, mealworm beetle.
Answer 19.
The young and adults do not compete with each other for the same food. Each stage is suited to where it lives and what it eats, so more individuals are able to find enough food and survive.
Answer 20.
Any two differences:
- A three-stage life cycle has no pupa stage, but a four-stage life cycle does.
- The young in a three-stage life cycle (nymph) looks similar to the adult, while the young in a four-stage life cycle (larva) looks very different from the adult.
- A three-stage life cycle goes egg → nymph → adult; a four-stage life cycle goes egg → larva → pupa → adult.
END OF ANSWER KEY