Which of the Following Statements About the Value of the Nitrogen

Which of the following statements about the value of the nitrogen cycle to an ecosystem is NOT true?

A) Denitrification removes nitrogen from the atmosphere and converts it to a form that plants can use.
B) Nitrogen fixation can occur in aquatic systems or in soil bacteria.
C) Nitrification occurs as ammonium is converted to nitrate.
D) Nitrification occurs as nitrogen gas is converted to nitrate.
E) Both ammonium and nitrate ions are highly water-soluble