Which molecule is responsible for maintaining continuity between generations in living organisms?

The link between generations is provided by:

Which of the following nitrogen bases is found only in $DNA$?

$A$ distinct mechanism that usually involves a short segment of $DNA$ with a remarkable capacity to move from one location in a chromosome to another is called:

In $B-DNA$,the rise per base pair would be

Statement $P$: Uracil is not present in the structure of $DNA$.
Statement $Q$: $A-T$ complementary base pairing is present in the structure of $DNA$.