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Primary General Studies: Food Chains and Ecology (Paper 4 (error clinic))
Primary General Studies: Food Chains and Ecology (Paper 4 (error clinic))
Paper four re-drills the most common errors from the first three papers, with different numbers throughout.
Direct answers Write the role or the number of levels on rough paper first, then the numbers, and sanity check the result at the end.
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)
- FoundationOf grass, rabbit and bacteria, which one is the producer?
- Foundation20 000 units of energy pass two levels keeping one tenth each time. How much reaches the second?
- FoundationWhich way should the arrow in a food chain point?
- IntermediateA vegetable field has 400 insects and spraying leaves 25 per cent. How many remain?
- IntermediateFour birds each eat 20 insects a day. How many are eaten in one day?
- IntermediateA grassland covers 6 000 square metres with 4 plants per square metre. If 200 plants feed one rabbit, how many rabbits fit?
- Challenge80 000 kJ passes three levels keeping one tenth each time. How much reaches the third?
- ChallengeA rabbit population of 400 falls 25 per cent a year. How many after two years?
- ChallengeA forest has 4 000 squirrels and disease cuts 15 per cent a year. How many after two years?
- Error redoA classmate says protecting the eagle keeps the whole chain safe. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Only the grass is a producer. | The rabbit is a consumer and the bacteria are decomposers, so the roles must not be mixed up. |
| 2 | The second level gets 200 units. | 20 000 divided by 10 is 2 000, and again by 10 gives 200. |
| 3 | From the organism being eaten to the one that eats it. | The arrow marks the direction of energy flow, and reversing it makes the whole chain wrong. |
| 4 | 100 insects remain. | 400 times 0.25 is 100. |
| 5 | 80 insects are eaten. | 4 times 20 is 80, which is why the pest numbers fall. |
| 6 | It can support 120 rabbits. | 6 000 times 4 is 24 000 plants, and 24 000 divided by 200 is 120. |
| 7 | The third level gets 80 kJ. | Divide by ten three times: 80 000, 8 000, 800, then 80. |
| 8 | About 225 rabbits. | 400 times 0.75 is 300, and again gives 225, which is not the same as losing 100. |
| 9 | About 2 890 squirrels. | 4 000 times 0.85 is 3 400, and 3 400 times 0.85 is 2 890. |
| 10 | Every link depends on the ones below, so damage to plants or habitat still wipes out the top predator. | Conservation has to protect the whole system, not just one animal. |
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.
With all four done, go back to the chapter page and revise the three parts of a closed circuit plus three safety habits.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.