Question 39
Question 39 of 40
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No letter options?
Older MCQs might not have the typical A, B, C, D choices. They have choices 1, 2, 3, and a combination of them is the answer. Below is the key that maps such combinations to the answer.
A 1, 2 and 3 are correct
B 1 and 2 only are correct
C 2 and 3 only are correct
D 1 only is correct
Topics Tested
20. Human influences on e...
20.3. Pollution

Describe the sources and effects of pollution of the air by methane and carbon dioxide, limited to: the enhanced greenhouse effect and climate change

6. Plant nutrition
6.1. Photosynthesis

Investigate and describe the effects of varying light intensity, carbon dioxide concentration and temperature on the rate of photosynthesis

11. Gas exchange in human...
11.1. Gas exchange in humans

Explain the link between physical activity and the rate and depth of breathing in terms of: an increased carbon dioxide concentration in the blood, which is detected by the brain, leading to an increased rate and greater depth of breathing