Which of the following switch off lac operon

Repressor protein is formed from

Wild type E.coli cells are growing in normal medium with glucose. They are transferred to a medium containing only lactose as the sugar. Which one of the following changes take place

In the lactose operon of Escherichia coli, what is the function of promoter

How many of the given statements $(i-iv)$ is/are correct?

$i.$ In transcription, adenosine pairs with uracil.

$ii.$ Regulation of lac operon by repressor is referred to as positive regulation.

$iii.$ The human genome has approximately $50,000\; genes.$

$iv. $ Haemophilia is a sex-linked recessive disease.

The lactose present in the growth medium of bacteria is transported to the cell by the action of