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? A) Draining the swamp helps keep the humidity down. B) Draining the swamp destroys the habitat the animals require. C) Draining the swamp will lead many animals to adopt new roles in the local ecosystem. D) Draining the swamp is actually just as good for the swamp residents as it is for the people building.