Which of the following statements is incorrect regarding the $DNA$ model proposed by Watson and Crick?

In the structure of $DNA$,with which nitrogenous base does adenine $(A)$ always pair?

Which of the following sequences is used to determine phylogenetic history?

$S$ Statement: $DNA$ is inherited by organisms produced by parents.
$R$ Reason: $DNA$ acts as a gene.
$(a)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(b)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(c)$ $S$ is true and $R$ is false.
$(d)$ $S$ is false and $R$ is true.
$(e)$ Both $S$ and $R$ are false.

Which sugar is found in $RNA$?

State the characteristic feature of $DNA$ in organisms.