In his experiments with different competing pairs of Paramecium species, Gause found that sometimes both species persisted and sometimes only one species did. Which hypothesis did Gause propose in order to explain the cases in which both species persisted?
A) One species was a much better competitor than the other.
B) Periodic disturbance allowed for coexistence.
C) The two species tended to use different resources.
D) The two species exhibited only interference competition, not exploitative competition.