$A$ $DNA$ strand is directly involved in the synthesis of the following,except:

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?

$DNA$ strand is directly involved in the synthesis of all the following except:

What is central dogma and describe the packing of $DNA$ helix?

In which of the following is the flow of genetic information in the reverse direction?

$DNA$ generally acts as a template for the synthesis of: