Define the following terms: Replication fork and Transcription.

Which of the following statements is incorrect?

Consider the following four statements $(a-d)$ and select the option which includes all the correct ones only $:-$
$(a)$ Transcription and translation can be coupled in bacteria.
$(b)$ The split gene arrangements represent the advanced feature of the genome.
$(c)$ The process of splicing represents the dominance of $\text{RNA-}$world.
$(d)$ The presence of introns in split gene is reminiscent of antiquity.

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?

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

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