What Is True About the Nitrogen Cycle

Multiple Choice

What is true about the nitrogen cycle?

A) The form of nitrogen present in significant levels in the atmosphere is easily assimilated by most organisms.
B) Most of the nitrogen in the atmosphere exists as organic molecules.
C) The activity of specific types of microorganisms is important to convert atmospheric nitrogen molecules into usable forms.
D) Both most of the nitrogen in the atmosphere exists as organic molecules and the activity of specific types of microorganisms is important to convert atmospheric nitrogen molecules into usable forms.
E) All organisms can incorporate atmospheric nitrogen into their proteins and nucleic acids.