Which of the following factors would be a likely reason for low population density?
a) a harsh natural environment
b) being located by a harbor
c) having abundant natural wealth
d) low infant mortality rates

A harsh natural environment is a factor that directly influences population density. This is because for an organism to survive in a given area, the conditions or environment surrounding it needs to either be favourable or directly support it's existence. If the environment is harsh it is automatic that organisms will seek a more favourable area therefore creating a high population density where conditions support their existence.

It is c. naturally in the environment

Increasing the release of greenhouse gases and pollution