O-LevelBiologyEcology & Environment5090/11 · Oct/Nov 2013 · Q321 Mark

The graph shows how the pH of a lake has changed in the period 1500 AD to 2000 AD. What could have caused the change in the pH over the last 100 years?

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Aburning of fossil fuels in factories

Bconversion of nearby woodlands to agricultural land

Cincreased growth of plants in the lake

Duse of insecticides on nearby fields

✓ Correct answer

A: burning of fossil fuels in factories

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Topic: Ecology & Environment, O-Level Biology (syllabus 5090). Multiple choice, 1 mark.
Source: O-Level Biology, Oct/Nov 2013 Paper 1 Variant 1, question 32.

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