Concept:DNA replication needs a specific enzyme to join nucleotides into new DNA strands.Explanation:The enzyme DNA polymerase adds complementary nucleotides to the template strand during replication.It catalyses the formation of phosphodiester bonds between nucleotides.Ptyalin and amylase both act on starch.Pepsin digests proteins in the stomach.Only polymerase is responsible for DNA replication.Answer:A. polymerase