This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
The gaps between segments of DNA on the lagging strand produced by restriction enzymes are rejoined/sealed by 
Select and explain. 
A. DNA ligases, B. DNA helicase, C. DNA topoisomerase, D. DNA phosphorylase
A: DNA ligases
Answer: A: DNA ligases 
Explanation: In molecular biology, DNA ligase is a specific type of enzyme, a ligase, that facilitates the joining of DNA strands together by catalyzing the formationHelicase action in DNA replication. Helicases are often used to separate strands of a DNA double helix or a self-annealed RNA molecule using the energy from ATP hydrolysis, a process characterized by the breaking of hydrogen bonds between annealed nucleotide bases.Topoisomerases are enzymes that paicipate in the overwinding or underwinding of DNAPhosphorylases are enzymes that catalyze the addition of a phosphate group from an inorganic phosphate