In the following passage, some words have been deleted. Fill in the blanks with the help of the alternatives given. Select the most appropriate option for each number.

James Dewey Watson was born in Chicago on 6 April 1928. In 1947, he received a B.Sc. degree in Zoology. During these years his interest in bird-watching had matured into a serious ____ (1) ____ to learn genetics. This became possible when he received a Fellowship for graduate study in Zoology at Indiana University, Bloomington, where he received his Ph.D. degree in 1950 on a study of the _____ (2) _____ of hard X-rays on bacteriophage multiplication. He met Crick and discovered _____ (3) _____ common interest in solving the DNA structure. Their first serious effort was ____(4)_____. Their second effort based upon more experimental evidence and better appreciation _____ (5) _____ the nucleic acid literature, resulted, early in March 1953, in the proposal of the complementary double-helical configuration.