<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>
Answer:

Explanation:
We need to find the energy produced when Sun converts 1.7 kg of mass into energy. Einstein's mass energy relation is given by :

c is speed of light

So, energy produced is
.
Answer:
For example, a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community. A brief treatment of biological communities follows. ... The various species in a community each occupy their own ecological niche.
Answer:
The answer is natural selection.
Explanation:
Natural selection will make an organism to survive and reproduce because, it will be better suited to the environment.
This is the reason why natural selection is considered as a key mechanism of the evolution.