This passage consists of six sentences. The first and the sixth sentence are given in the beginning as S1 and S6. The middle four sentences in each have been removed and jumbled up. These are labelled P, Q, R and S. You are required to find out the proper sequence of the four sentences and mark your response accordingly on the Answer Sheet. S1: Science has already conferred an immense boon on mankind by the growth of medicine. S6: The general death rate in 1948 (10.8) was the lowest ever recorded up to that date. P: It has continued ever since and is still continuing. Q: In the eighteenth century people expected most of their children to die before they were grown up. R: In 1920 the infant mortality rate in England and Wales was 80 per thousand; in 1948 it was 34 per thousand. S: Improvement began at the start of the nineteenth century, chiefly owing to vaccination. The proper sequence should be