O-LevelBiologyEcology & Environment5090/11 · Oct/Nov 2017 · Q301 Mark

In a fish tank, bacteria recycle animal waste for plants to use. The diagram shows some of the stages in this process. What are compounds 1, 2 and 3?

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A1: ammonia, 2: nitrates, 3: nitrites

B1: ammonia, 2: nitrites, 3: nitrates

C1: nitrates, 2: ammonia, 3: nitrites

D1: nitrites, 2: ammonia, 3: nitrates

✓ Correct answer

B: 1: ammonia, 2: nitrites, 3: nitrates

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Topic: Ecology & Environment, O-Level Biology (syllabus 5090). Multiple choice, 1 mark.
Source: O-Level Biology, Oct/Nov 2017 Paper 1 Variant 1, question 30.

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