Human influences on the environment

Question 2

The discharge of untreated sewage into a river affects the abundance of various organisms living in the water. The graph below shows the changes in the relative abundance of mayfly nymphs, green algae, and decomposing bacteria before and after a sewage discharge point. Mayfly nymphs are aquatic insects that are highly sensitive to dissolved oxygen levels.

Graph showing the relative abundance of mayfly nymphs, green algae, and decomposing bacteria along a river before and after a sewage discharge point

Explain the changes in the populations of mayfly nymphs and green algae from the point at which the sewage enters the river.

[6]

Human influences on the environment

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Question 2

The discharge of untreated sewage into a river affects the abundance of various organisms living in the water. The graph below shows the changes in the relative abundance of mayfly nymphs, green algae, and decomposing bacteria before and after a sewage discharge point. Mayfly nymphs are aquatic insects that are highly sensitive to dissolved oxygen levels.

Graph showing the relative abundance of mayfly nymphs, green algae, and decomposing bacteria along a river before and after a sewage discharge point

Explain the changes in the populations of mayfly nymphs and green algae from the point at which the sewage enters the river.

[6]

Human influences on the environment

Question 2

Human influences on the environment Questions

Human influences on the environment

Question 2

Human influences on the environment Questions