Question

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

Answer 1

A beavers won't build dams of their own
B large amounts of electricity can be produced, without contributing to air pollution
C it produces a lake, which is great for water skiing

Answer 2

b