<span>It sounds like he has post tramatic stress disorder from coming back from overseas. He would be recommend to take medicine and go to therapy to help him know how to get back into his regular family life. I'm sure it's extremely hard.</span>
It is the natural/genetic ability of an organism to avoid or repel attack by biotic agents (pests etc.) or to withstand the effects of abiotic agents example (chemicals).
Answer:
The nitrogen cycle is a repeating cycle of processes during which nitrogen moves through both living and non-living things: the atmosphere, soil, water, plants, animals and bacteria. In order to move through the different parts of the cycle, nitrogen must change forms.
