The genes are in the form of

In sea urchin $DNA$,which is double stranded,$17\%$ of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this $DNA$ are

Assertion: In a $DNA$ molecule,$A-T$ rich parts melt before $G-C$ rich parts.
Reason: In between $A$ and $T$ there are three $H-$ bonds,whereas in between $G$ and $C$ there are two $H-$ bonds.

In a $DNA$ molecule,if cytosine is $18\%$,then the percentage of adenine would be: (in $\%$)

If the sequence of one strand of $DNA$ is written as follows:
$5'- ATGCATGCATGCATGCATGCATGCATGC-3'$
Write down the sequence of the complementary strand in the $5' \rightarrow 3'$ direction.

......... is responsible for hereditary traits in all living organisms.