What have we learned about rna in the 60 years

RNA consists of four nitrogenous bases :

Later, in 1960, the discovery that an RNA molecule and a DNA molecule could form a hybrid double helix was the first experimental demonstration of a way in which information could be transferred from DNA to RNA ( Rich, 1960 ).

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.

the answers are a and c