Can be a number of things, rain fall quota, climate, population, vegetation..any of those.
Answer:
Nitrogen is a naturally occurring element that is essential for growth and reproduction in both plants and animals. It is found in amino acids that make up proteins, in nucleic acids, that comprise the hereditary material and life's blueprint for all cells, and in many other organic and inorganic compounds.
Explanation:
(I just copy and paste from google)
