Taylor and his colleagues proved that $DNA$ in chromosomes also replicates semi-conservatively. Which organism did they use for this experiment?

Identify parts $A, B, C, D$ in the figure given below:

Given below are the two statements.
Statement $I$: In prokaryotes,there is only one replicon,however,in eukaryotes,there are several replicons in tandem.
Statement $II$: The two separated strands in a replicon of $DNA$ are prevented from rejoining by helicase enzyme.
In the light of the above statements,choose the correct answer from the options given below.

The process of $DNA$ multiplication is called:

The Okazaki fragments in $DNA$ chain:

During replication of $DNA$, the $RNA$ primers are removed by i and replaced by $DNA$ sequences with the help of ii in prokaryotes and iii in eukaryotes.