The structural formula of the pentose sugar present in $DNA$ is given. Select the correct group for the position marked '$X$' from the options.

Read the following four statements ($1$ to $4$):
$1$. In transcription,uracil pairs with adenosine.
$2$. Regulation of $lac$ operon by a repressor is referred to as positive regulation.
$3$. The human genome contains approximately $50,000$ genes.
$4$. Haemophilia is a sex-linked recessive disease.
How many of the above statements are correct?

Which of the following statements is incorrect?

Find the incorrect statement $:$

Read the following statements $:-$
$(i)$ Eukaryotic $\text{mRNA}$ is polycistronic whereas prokaryotic $\text{mRNA}$ is monocistronic.
$(ii)$ Prokaryotic $\text{mRNA}$ is cap-less and tail-less whereas eukaryotic $\text{mRNA}$ is with cap and tail.
$(iii)$ The precursor of prokaryotic $\text{mRNA}$ is $\text{hnRNA}$.
$(iv)$ In replication,only one of the strands acts as a template.
$(v)$ In eukaryotes,transcription occurs in the nucleus and translation in the cytoplasm.
Which of the above statements are correct?

Mark the correct match.