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Which of the following statements about the poly(A) tails that are found on most eukaryotic mRNAs is correct?
A.
They are added as preformed polyriboadenylate segments to the 3 ′ ends of mRNA precursors by an RNA ligase activity.
B.
They are encoded by stretches of polydeoxythymidylate in the template strand of the gene.
C.
They are added by RNA polymerase II in a template-independent reaction using ATP .
D.
They are added by poly(A) polymerase using ATP and the conservative AAUAAA sequence is required .