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

In which process is nucleic acid synthesized from nucleic acid?

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?

Define the following terms: Replication fork and Transcription.

After a mutation at a genetic locus,the character of an organism changes due to the change in:

Which one of the following is wrongly matched?