question_answer

A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this?

[a] Lots of urea and phosphate fertilizer were used in the crops in the vicinity

[b] The area was sprayed with DDT by an aircraft

[c] The lake water turned green and stinky

[d] Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis. Which two of the above were the main causes of fish mortality in the lake?

A)  b, c     

B)  c, d

C)  a, c     

D)  a, b