Question

When building in a swampy or marshy area, it is usually necessary to drain the swamp before starting to build. While this is good for people, it may not be for animals that were living in the swamp. Why?

Answer 1

maybe because some of the animals that live in a swamp are adapted to the area that the people are building on 

Answer 2

Draining the swamp is not good, but must be weighed against factors like the human need for housing.