Which characteristics of DNA polymerase I raised doubts that its in vivo function is the synthesis of DNA leading to complete replication?

The question is incomplete. The complete question is as follows:

Which characteristics of DNA polymerase I raised doubts that its in vivo function is the synthesis of DNA leading to complete replication?

its composition of a single polypeptide chain.

deficiency of enzyme in some organisms that are still capable of DNA synthesis.

requirement of Mg2 + presence in order for the enzyme to work.

low stability under normal physiological conditions.

Answer:

Deficiency of enzyme in some organisms that are still capable of DNA synthesis

Explanation:

The DNA polymerase I may be defined as the important enzyme that play an important role in the DNA replication of prokaryotes. DNA pol I is the replicating enzyme, DNA repair enzyme and can also acts as the exonuclease.

DNA pol I has been studied invitro and Arthur Korenberg explain the discovery of the DNA pol I. This DNA pol I plays an important role in DNA repair rather than the replication process. This explained invivo by the fact that some in some organisms the deficiency of this enzyme do not halt the process of replication. If the DNA pol I acts as the main replaicating enzyme, the DNA synthesis must be stopped in the organisms that lack DNA synthesis.

Thus, the correct answer is option (2).