21. For the sequence of dsDNA given below, identify the set of primers required to amplify this DNA by PCR.
3' GACTCCA . . . . . . . . TACAACC 5'
5' CTGAGGT . . . . . . . . ATGTTGG 3'
3' GACTCCA . . . . . . . . TACAACC 5'
5' CTGAGGT . . . . . . . . ATGTTGG 3'