Question
The flow diagram shows a process that can occur as a result of pollution in a river.
Which term describes the process shown in the flow diagram?
A aerobic respiration
B eutrophication
C nitrogen cycle
D photosynthesis
Answer/Explanation
Ans
B
Question
Which stage in the treatment of sewage removes large floating objects, such as plastic bags?
A aeration
B discharge
C screening
D sedimentation
Answer/Explanation
Ans
C
Question
The diagram shows the positions of four farms and the concentrations of nitrate at different points
in a river.
Which farm is likely to have been using too much fertiliser on its land?
Answer/Explanation
Ans: A
Question
When nitrates enter a lake they cause rapid growth of algae on the surface of the water. This causes the following changes in the lake:
1 a decrease in the concentration of dissolved oxygen in the water
2 fish and other aquatic animals die
3 an increase in aerobic respiration by decomposers
4 producers die and decomposition increases
In which order do these changes occur?
A 1 → 2 → 4 → 3
B 3 → 1 → 2 → 4
C 4 → 2 → 3 → 1
D 4 → 3 → 1 → 2
Answer/Explanation
Ans: D