What is a cause of nonpoint-source pollution?
nonpoint-source pollution
boats and jets skis on a lake
point-source sollution
sludge
trash dumping
adopt-a-beach

Boats and jets skis on a lake

Explanation:

A non-point source pollution is the one which does not originate from a single source instead it originates from the multiple sources. The sources of origin always remains undetermined hence, the pollutants cannot trace back to their source of origin and cannot be controlled.

Among the options given,  Boats and jets skis on a lake. is the correct option. This is because of the fact that the boats and jet skies are likely to release pollutants like oils and remains of the combustible fuels. These vehicles are mobile and hence, the source of origin will remain undetermined. Hence, the option is the example of non-point source pollution.  

the correct answer is:

a population changes in response to a change in the environment.

the answer would be knowledge about cars!