Which is the functional unit of inheritance?

The base sequence for a nucleic acid segment is given as $CAG, AGG, CGA, CCA$. From this,it can definitely be concluded that it is a segment of:

In the structure of $DNA$,if one nitrogenous base is adenine,which nitrogenous base pairs with it?

If a $DNA$ fragment contains $A = 166$ and $C = 144$,what is the total number of nitrogenous base pairs in that fragment?

In the polynucleotide chain of $DNA$,a nitrogenous base is linked to the $-OH$ of

Describe the structure of $DNA$ as proposed by Watson and Crick.