Tundra Is Divided into Alpine Tundra at the Top of Mountains

Tundra is divided into alpine tundra at the top of mountains and arctic tundra found close to the North Pole.These two biomes have similar plants and animals even though they can be located in vastly different regions of the world.What causes these two biomes to be similar?

A) Both are found close to coniferous forests.
B) One is cold and dry because it is at a high latitude and the other is cold and dry because it is at a high altitude.
C) Both are located in areas of intense sunshine.
D) One grows mostly grasses because the soil is poor and the other grows mostly grasses because the soil is frozen.
E) Both have large grazing herds that keep the grasses clipped short.