In this section each item consists of six sentences of a passage. The first and sixth sentences are given in the beginning as S1 and S6. The middle four sentences in each sequence have been jumbled up and labelled as P, Q, R and S. You are required to find the proper sequence of the four sentences and mark your response accordingly on the Answer Sheet.

S1: Ecology, history and geography determine the distribution of organisms.
S6: Others prefer to interpret biogeographical history through vicariance (range-splitting) events.
P: Some historical biogeographers are interested in finding centre-of-origins.
Q: Most species distributions result from a combination of all these factors.
R: But biogeographers tend to specialise in ecological aspects (ecological biography or historical aspects).
S: Ecological biogeographers are interested in the effects of environmental factors.
The correct sequence should be

Options