Final answer:
E. coli DNA Pol III is a holoenzyme with high processivity important for DNA synthesis, while Pol I is multifunctional, involved in DNA repair and removal of RNA primers.
Step-by-step explanation:
A characteristic of E. coli DNA polymerases is that Pol III functions as a holoenzyme that polymerizes DNA with high processivity. In other words, DNA Pol III is the enzyme required for DNA synthesis and operates with high efficiency and speed, adding nucleotides to a growing DNA strand without dissociating frequently. Pol I functions as a multifunctional protein that participates in DNA repair and also possesses a 5→3' exonuclease activity, which is important for the removal of RNA primers used during DNA replication. This exonuclease activity part of Pol I can be detached by mild protease treatment, leaving behind the Klenow fragment that retains the polymerization and proofreading activities.