<prompt> Most important enzyme in DNA replication for chain elongation -HelicaseDNA polymerase IDNA polymerase IIITopoisomerase III  <response>: Ans. is c i.e., DNA polymerase IIImportant DNA PolymerasesIn Prokaryoteso DNA polymerase I:- Helps in gap filling and synthesis between okazaki fragments of lagging strand, and replaces ribonucleotides of RNA primer by deoxyribonucleotides. It has i 31 - 51 exonuclease activity, ii 51 - 31 exonuclease activity and iii polymerase 51 - 31 polymerase activityo DNA polymerase II:- Helps in i proof reading 31 - 51 exonuclease activity, and ii DNA repairo DNA polymerase III:- It is the main enzyme that synthesizes prokaryote DNA, i.e., synthesis of leading and lagging strand. It has i 51 - 31 polymerase or simply polymerase activity for DNA synthesis, and ii 31 - 51 exonuclease activity for proof reading.In Eukaryoteso DNA polymerase a:- It has primase activity i.e. synthesizes RNA primer, and initiates DNA synthesiso DNA polymerase b:- It is a DNA repair enzymeo DNA polymerase g:- Replicates mitochondrial DNAo DNA polymerase d:- Helps DNA synthesis on lagging strand, i.e. elongation of okazaki fragments on lagging strand. It also has 51-31 exonuclease activity for proof reading.o DNA polymerase e:- Helps in DNA synthesis on leading strand. It also has 51 - 31 exonuclease activity for proof reading. 