Which enzyme is responsible for replacing RNA primers on newly synthesized DNA strands and is needed much more frequently on the lagging strand than on the leading strand?

DNA polymerase I

Explanation:

DNA polymerase I have a distinct 5' to 3' exonuclease activity. This allows the DNA polymerase I to remove a segment of DNA or RNA that is paired with the template strand. Due to the presence of its 5' to 3' exonuclease activity, DNA polymerase I can remove the primers from the newly formed DNA strands. Since the lagging strand is replicated by the formation of Okazaki fragments, it requires DNA polymerase I to remove primers from each of the Okazaki fragments.