Question
The careless use of nitrogenous fertilizer near rivers and lakes can cause eutrophication.
This results in the death of fish.
What is the direct cause of the death of the fish?
A Decomposers reduce the amount of dissolved oxygen in the water.
B Nitrates are toxic to plants.
C The rapid growth of producers uses up all the available nutrients.
D The sudden increase in the number of bacteria increases the spread of disease.
Answer/Explanation
Ans
A
Question
The diagram shows part of the carbon cycle.
Which process reduces the carbon dioxide content of the atmosphere?
Answer/Explanation
Ans
B
Question
The diagram shows some of the stages involved in the nitrogen cycle.
Answer/Explanation
Ans
B
Question
Which organisms are responsible for removing nitrate ions from soil?
A denitrifying bacteria and nitrogen-fixing bacteria in root nodules
B denitrifying bacteria and plants
C nitrifying bacteria and plants
D nitrogen-fixing bacteria in root nodules
Answer/Explanation
Ans: B