Primary General Studies: Food Chains And Ecology (Paper 1 (basics))

Primary General Studies: Food Chains and Ecology (Paper 1 (basics))

2026-11-13

Tutor Prep Guide · Food chains, producers and consumers, energy flow and ecological balance

Primary General Studies: Food Chains and Ecology (Paper 1 (basics))

Paper one covers producers, consumers and the flow of energy, moving from easy to harder sums that can all be checked with the four operations.

Direct answers　Find the starting point before answering a chain question, write down the one tenth step before an energy question, and check that the result is sensible.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: Primary General Studies: Food Chains and Ecology
Level	parts of a closed circuit, conductors against insulators, series against parallel, adding up battery voltage, and electrical safety

02　Questions (10 items)

FoundationIn the food chain grass, rabbit, eagle, which living thing is the producer?
FoundationBesides sunlight and water, which gas do plants take in for photosynthesis?
FoundationThe grass holds 10 000 units of energy and the rabbit keeps one tenth. How much does the rabbit get?
IntermediateOne frog eats 15 insects a day. How many do 5 frogs eat in 7 days?
IntermediateA food web has three routes: grass, insect, frog, snake; grass, mouse, snake; grass, mouse, eagle. How many food chains are there?
IntermediateOne eagle needs 10 rabbits, and 10 rabbits need how many plants if each level keeps one tenth?
ChallengeA field has 500 insects and pesticide leaves 20 per cent. Five frogs need 20 insects each a day. Is what is left enough for one day?
ChallengeIf each level keeps one tenth of the energy, what percentage is left after three levels?
ChallengeA meadow grows 12 000 kg of plants a year. Herbivores take one tenth and carnivores take one tenth of that. How much do the carnivores get?
Error redoA classmate writes the chain as eagle, rabbit, grass. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	The grass is the producer.	A producer makes its own food from sunlight, so it always starts the chain.
2	Carbon dioxide.	Photosynthesis takes in carbon dioxide and gives out oxygen.
3	The rabbit gets 1 000 units.	10 000 times 0.1 is 1 000, because each level keeps about one tenth.
4	They eat 525 insects.	15 times 5 is 75 a day, and 75 times 7 is 525.
5	There are 3 food chains.	Each route from the producer to a top predator counts as one food chain.
6	They need 100 plants.	10 times 10 is 100, so the lower levels of an energy pyramid hold far more living things.
7	100 insects are left, just enough for five frogs for one day, and short the next day.	500 times 0.2 is 100 and 5 times 20 is also 100, so the supply only just balances.
8	0.1 per cent is left.	0.1 to the power of three is 0.001, which is 0.1 per cent.
9	They get 120 kg.	12 000 times 0.1 is 1 200, and 1 200 times 0.1 is 120.
10	The direction is reversed. A chain starts with the producer and the arrow points to the eater.	Energy flows from grass to rabbit to eagle, so the order cannot be turned around.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

After paper one, take paper two and sort out series against parallel in one pass.Tutor Registration →

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