Will give a brainlest savannas do not exist in the united because they have been destroyed by overgrazing the climate is too extreme they are found only in africa they exist only in the tropics

Savannas can be found anywhere but must be located in a tropical climate to thrive.
The U.S.A. has a very moderate climate, and for the most part is the same overall. Thus, a savanna wouldn't be able to exist in the U.S.A without the tropical climate, which means all 12 months have temperatures around 64 degrees Fahrenheit, and there are only two seasons: wet and dry.
 As opposed to the U.S.A's Moderate Springs, Blazing summers, chilly falls, and cold winters (may fluctuate depending on the state), a savanna wouldn't be able to thrive.

Your answer is D: they exist only in the tropics.
~Hope this helps!