What is a keystone species?

Options

A. A dominant species that constitutes a large proportion of the biomass and which affects many other species
B. A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community's organization and survival
C. A common species that has plenty of biomass, yet has a fairly low impact on the community's organization
D. A rare species that has minimal impact on the biomass and on other species in the community

Answer

B