The length of one full turn of $B-DNA$ is ....... (in $nm$)

Assertion $(S)$: $RNA$ does not contain $T$ (Thymine).
Reason $(R)$: $DNA$ does not contain $U$ (Uracil).

If the distance between two consecutive base pairs in a $DNA$ molecule is $0.34 \ nm$ and the total number of base pairs in a typical mammalian cell is $6.6 \times 10^9 \ bp$,what is the approximate length of the $DNA$ (in $m$)?

Which polypeptide chains are present in $Hb F$ (Foetal Haemoglobin)?

Which of the following is not applicable to $RNA$?

In $DNA$,how are the nucleotides linked together?