Choose the correct option regarding the origin of replication $(ori)$.

Synthesis of leading and lagging strand require

The monomer of $DNA$ is deoxyribonucleotide. However,why is deoxyribonucleoside triphosphate used at the enzymatic site?

Primase is a type of ...........

Which enzyme is responsible for linking the fragments of $DNA$?

Ten $E. coli$ cells with $^{15}N$-dsDNA are incubated in a medium containing $^{14}N$ nucleotides. After $60$ minutes, how many $E. coli$ cells will have $DNA$ totally free from $^{15}N$ (in $cells$)?