Which of the Following Is Correct

Which of the following is correct?

A) Nitrogen is an important element in amino acids,proteins,and cholesterol.
B) Plants lacking a symbiotic nitrogen-fixing partner must rely on nitrogen compounds in the soil.
C) Most commercial fertilizers contain nodules with nitrogen-fixing bacteria.
D) A positive effect of nitrogen fertilizer application is that it can cause huge population increases of algae called "algal blooms."
E) Humans have had little impact on the nitrogen cycle,even with the burning of fossil fuels.