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CAIE IGCSE Biology 20.3 Pollution Question Bank

Practise pollution questions by interpreting sewage and fertiliser effects, tracing plastic hazards and explaining greenhouse gases or eutrophication.

Syllabus
2026–2028
Course
Biology 0610

Exam points

  • interpret sewage or fertiliser data using bacteria, nitrate, oxygen and fish evidence
  • trace non-biodegradable plastics through marine or terrestrial food chains
  • sequence eutrophication from nitrate ions to producer growth, decay and oxygen loss

Covered syllabus points

20.3.1—Effects of untreated sewage and excess20.3.2—Effects of non-biodegradable plastics20.3.3—Sources and effects of pollution20.3.4—Process of eutrophication of water

20.3 Pollution question 1

[Maximum number: 6]

Waste from livestock farms often pollutes water courses, such as streams and rivers, leading to a reduction in biodiversity.

Explain how the pollution of water courses by animal waste leads to a reduction in biodiversity.

20.3 Pollution question 2

[Maximum number: 2]

Phytoplankton are producers found in the ocean. Phytoplankton absorb microplastics into their cells.

Fig. 6.2 shows a shearwater bird.

Shearwater birds feed on fish in the ocean.

Fig. 6.2

Fig. 6.2

Suggest how microplastics can end up in consumers such as shearwater birds.

20.3 Pollution question 3

[Maximum number: 3]

Fig. 6.1 shows part of the carbon cycle in the ocean.

Fig. 6.1 (not to scale)

Fig. 6.1 (not to scale)

Describe the effect on the environment of additional carbon dioxide in the atmosphere.

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