Elephants Are Not the Most Dominant Species in African Grasslands

Elephants are not the most dominant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario?

A) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.
B) Elephants help other populations survive by keeping out many of the large African predators.
C) Grazing animals depend upon the elephants to convert forests to grasslands.
D) Elephants are the biggest herbivore in this community.
E) Elephants prevent drought in African grasslands.