Directions: 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 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: If we dump sewage into a stream, on a small scale, the stream dissolves it and purifies it.

S6: For this overwhelming kind of pollution we need to coin a new term which we call super-pollution.

P: It can no longer deal even with the small quantity of sewage which it once accepted without difficulty.

Q: Ten miles downstream the water is pure again.

R: The system has broken down.

S: But if we dump large quantities of sewage, we end by killing the purifying bacteria and then the stream has lost its power to purify.