List 5 reasons why earth is under populated

The earth is unpopulated by natural causes yet many causes in people all over the earth some personal reasons could be do to: infertility, still -born births, misc arriage, and health problems. But as proved and seen today there are many natural causes such as:  kill ings, police bru tality , life- threa tening diseases, dome stic viole nce, suic ide, and many things that go unnoticed  in communities around us that causes earth to be unpopulated.  

Explanation:

Earth is actually beginning to get overpopulated. Just look at the poverty, pollution, deforestation, global warming, etc.

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.