40. According to the intermediate disturbance hypothesis, species richness is higher in areas of intermediate levels ofdisturbance. Why would species richness be lower at low levels of disturbance?
(A) A high nutrient level poisons lots of species.
(B) Competitive exclusion results in the extinction of species.
(C) Ecological niches are less partitioned in places with high levels of disturbance.
(D) Lack of disturbance slows down the evolution of new species.
(E) Low level of disturbance results in low soil fertility.