$DNA$ polymerase links nucleotides by forming which type of bond?

Bacteria were grown in a medium containing a heavy isotope of nitrogen $(^{15}N)$ for many generations,and all their $DNA$ contained only heavy nitrogen. $A$ bacterium of this type was transferred to a normal medium and allowed to duplicate. After two divisions,the distribution of heavy $DNA$ is likely to be:

Select the correct option for a eukaryotic cell regarding the origin of replication and the number of replication forks.

During the replication of a bacterial chromosome,$DNA$ synthesis starts from the origin of replication and proceeds in a.....

Choose the correct option for $Reverse \text{ } Transcriptase$.

If $E. coli$ is allowed to grow for $40$ minutes in a medium containing $^{15}N$,then the number of $^{14}N / ^{14}N$ containing $DNA$ molecules would be: