Why Is Tall Grass Prairie North America's Rarest Biome

Multiple Choice

Why is tall grass prairie North America's rarest biome?

A) Historically it only occurred in a very tiny region of North America.
B) Because over 90% of this biome has been converted to agriculture
C) Global warming has resulted in the conversion of most tall grass prairie to short grass prairie.
D) Pollution has degraded most of our tall grass prairie region.