Suppose primary productivity in an ecosystem has been limited by the amount of nitrogen present. If nitrogen levels flowing into the lake increases, which of the following events could occur?

A. The increase in nitrogen causes an increase in net primary productivity

B. The community structure changes

C. The mercury levels accumulate to toxic levels in the tissues of organisms in the upper trophic levels, but not in the lower trophic levels

D. All of the above

E. A and B, but not C

Question

Suppose primary productivity in an ecosystem has been limited by the amount of nitrogen present. If nitrogen levels flowing into the lake increases, which of the following events could occur?


A. The increase in nitrogen causes an increase in net primary productivity


B. The community structure changes


C. The mercury levels accumulate to toxic levels in the tissues of organisms in the upper trophic levels, but not in the lower trophic levels


D. All of the above


E. A and B, but not C

anonymous · Answer

I think it's E.
C. is absolutly wrong , because nitrogen has nothing to do with mercury .
and A. and B. sound right to me