By name or number, identify all of the following four actions that can be performed by DNA polymerase III: 1) Addition of a new nucleotide at the 5' end of a DNA strand 2) Addition of a new nucleotide at the 3' end of a DNA strand 3) Removal of a nucleotide at the 5' end of a DNA strand 4) Removal of a nucleotide at the 3' end of a DNA strand