<prompt> After digestion by restriction endonucleases DNA strands can be joined again by:DNA polymeraseDNA ligaseDNA topoisomeraseDNA gyrase  <response>: Ans. B. DNA LigaseRef: Harper 31e page434Enzymes involved in the DNA Replication1. TopoisomerasesRelieve torsional strain that results from helicase-induced unwinding of DNA.Nicking Resealing Enzyme2. Helicase: ATP driven processive unwinding of DNA3. Single Strand Binding Protein SSBPrevent premature reannealing of dsDNA4. DNA Primase:Initiates synthesis of RNA primers.Special class of DNA dependent RNA Polymerase5. DNA Polymerase: Catalyse the chemical reaction of DNA Polymerisation. Synthesise DNA only in 5 to 3 direction.6. DNA Ligase: Seals the single strand nick between the nascent chain and Okazaki fragments on lagging strand. 