What are some of the most detrimental sources of pollution in a watershed?

sperm

Explanation:

ejaculatory fluids pollute water sheds despite the fact that babies in their purest from are biodegradable

So that there is more gene variation. Let's say if they all had the same genes, one specific disease would be fatal for the species' existence since they would all be the same. The diverse gene pool allows species to develop different characteristics that can help them defend against disease