Natural biomes once covered nearly all of the land of the united states. how has the land of the united states changed today? a. about half of the land is now covered by anthromes, or human-altered biomes. b. nearly all of the land is now covered by anthromes, or human-altered biomes. c. human activities have removed wildlife from about half of the land. d. human activities have removed plant life from about half of the land.