On which organism did Taylor perform experiments to prove the semi-conservative mode of chromosome replication?

The mode of $DNA$ replication is predominantly ......

Name a few enzymes involved in $DNA$ replication other than $DNA$ polymerase and ligase. Name the key functions for each of them.

$DNA$ polymerase is required for:

The experimental system used in studies of the discovery of semi-conservative replication of $DNA$ was:

$A$ $DNA$ molecule in which both strands have radioactive thymidine is allowed to duplicate in an environment containing non-radioactive thymidine. What will be the correct number of $DNA$ molecules that contain some radioactive thymidine after three duplications?