Primary 5 · Science · Cycles: Life Cycles
Cycles: Life Cycles questions for Primary 5 Science
9 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.
- Reading a life cycle
- Comparing durations
- Comparing two cycles
- Choosing where to break a cycle
- Why cycles differ
- Three-stage and four-stage
- Naming a stage
- Applying the ideas
| Stage | Insect P (days) | Insect Q (days) |
|---|---|---|
| egg | 4 | 6 |
| larva or nymph | 18 | 30 |
| pupa | 9 | none |
| adult | 21 | 40 |
Same picture as the question above.
Answers and explanations for all 9 questions
Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.
According to the diagram above, at which stage does the frog first have legs?
Answer: the third stage
Legs grow while the animal is still a tadpole, which is the third stage in the diagram, before it becomes an adult frog.
Based on the table above, how much longer does insect Q take to reach adulthood than insect P?
Answer: 5 days
P takes 4 + 18 + 9 = 31 days to reach adulthood, and Q takes 6 + 30 = 36 days. The difference is 5 days.
Based on the same table, which two statements are correct?
Answer: A and B only
P's pupa row shows 9 days and Q's shows none, so only P has that stage. Q's adult lasts 40 days against P's 21.
A farmer wants to stop a beetle whose larvae eat his crop roots underground. Which stage is easiest to attack?
Answer: the eggs, which are laid on the soil surface
Attacking a cycle works best at the stage you can actually reach. The eggs are on the surface, so dealing with them prevents the larvae ever appearing.
Why is it an advantage for a butterfly's caterpillar to eat completely different food from the adult?
Answer: The young and the adults do not compete with each other for food.
Caterpillars eat leaves and adults drink nectar, so the two stages never take food from each other. Both can be abundant in the same place.
Which two statements about a three-stage life cycle are correct?
Answer: A and B only
Egg, nymph, adult is the three-stage pattern. The missing stage is the pupa, and the nymph resembles a small wingless adult.
Look at the second stage in the diagram above, which swims with a tail and breathes with gills. What is this stage called?
Answer: tadpole
The swimming stage of a frog's life cycle is the tadpole.
Between the larva and the adult, some insects spend a period inside a hard case, not feeding at all. What is this stage called?
Answer: pupa
The enclosed, non-feeding stage between larva and adult is the pupa.
Why do mosquito numbers rise sharply a week or two after heavy rain?
Answer: The rain leaves standing water where the first three stages can develop.
Egg, larva and pupa all need standing water. Rain fills every container and hollow, and a week or two later that generation emerges as adults.