A grassland ecosystem (ecosystem X) supports 13 different grass species. A different grassland ecosystem (ecosystem Y) supports just one species of grass. Bison graze on all of the grass species in both of these ecosystems. Ecosystem X 13 species of grass Ecosystem Y 1 species of grass A drought strikes both ecosystem X and ecosystem Y, but the bison in ecosystem X are better able to survive it. Which of the following is a likely explanation? A. The bison in ecosystem X only eat one species of grass. B. Ecosystem Y has a greater amount of biomass. C. Ecosystem X has a greater amount of biodiversity. D. Ecosystem Y has a greater amount of biodiversity.