The nitrogen cycle is important biologically because: The nitrogen cycle is not important biologically. The atmosphere is composed of 78% nitrogen; therefore, a. nitrogen is freely available to all living organisms, regardless of where it is in its cycle. b. nitrogen is a major constituent of phospholipids, ATP, and other energy-storing molecules. c. nitrogen is a component of amino acids, proteins, and nucleic acids. d. nitrogen forms the framework for organic molecules that are essential to all organisms. e. the processes in the mitochondria require major amounts of nitrogen.

option a. atmosphere contains 78% nitrogen, but it is in the crude form and very few organisms can absorb nitrogen in the atmosphere. so it is necessary for the nitrogen cycle to take place. therefore option a. is false

option b. ATP, adenosine triphosphate, contain Adenine, which has a portion of nitrogen. And nitrogen is known to be one of the main components of energy storing molecules.

option c. Nitrogen is an important part of amino acid, proteins and any of such.

option D. nitrogen is required for all organic molecules of organisms.