PLS HELP DONT HAVE MUCH TIME
Sometimes human actions can have both positive and negative environmental impacts.



A negative impact of a large, hydroelectric dam is that it backs up water sometimes for miles behind it, destroying natural habitat that once was there.


But a positive environmental impact of a dam is that

A.

large amounts of electricity can be produced, without contributing to air pollution


B.

beavers won't build dams of their own


C.

it produces a lake, which is great for water skiing


D.

it makes it easier for migrating fish to make it upstream to reproduce