The main purpose of a multiple cloning site is:

1. To keep the plasmid from leaving the nucleoid region.

2. To ensure the plasmid is copied many times in the bacterial cell.

3. To provide a location where DNA can be inserted into a plasmid.

4. To make it possible to eliminate bacteria that have not been genetically modified.

5. To ensure that each daughter cell receives a copy of the plasmid during cell division.