Most of the depopulation of the native american population in the 16th century can be attributed to a) disease. b) fires. c) slavery. d) war.

The answer to this question is: A. disease
Back then,  People still haven't developed vaccines or other form of antibiotics like we have today.
In 16th century, the naive american population was heavily decreased because of the small pox epidemic. Even though this illness could be easily treated today, during that time this illness was considered very lethal for the Native American people.