Which of the following is not present in $DNA$?

The $AT/GC$ ratio in human beings is (where $A = \text{adenine}$,$T = \text{thymine}$,$G = \text{guanine}$,$C = \text{cytosine}$)

Which of the following is not present in $RNA$?

Which of the following bases are present both in $DNA$ and $RNA$?

In $DNA$,the complementary bases are

In the double-strand helix structure of $DNA,$ thymine forms hydrogen bonds with