Answer:
Ampicillin in a plate do as to help in maintaining ampicillin resistance plasmid in the growing medium
Step-by-step explanation:
Ampicillin is an antibiotics that help to kill E.coli bacteria .
While growing bacteria in a plate or growing medium, it is important to add ampicillin to the plate so to maintain ampicillin resistance plasmid.
The absence of ampilicin, the bacteria will lose their resistance after they might have gone through some cell divisions and any bacteria that doesn't have resistance plasmid will be more vigorous than those that have and will outcompete them