From your results, can you tell if these bacteria are ampicillin resistant by looking at them on the lb plate?

Answer: Yes

It is possible to tell if the bacteria on the lb plate are ampicillin resistant just by looking at it because of the presence of colonies. This would indicate that ampicillin has lost its ability to effectively control or kill bacterial growth for it continues to multiply despite the presence of therapeutic level of ampicillin. Moreover, bacteria become resistant by gene mutation and by acquiring resistance from another bacterium through the widespread misuse of antibiotic.

I think the correct answer is yes because the plate with just ampicillin in it would have colonies if it was resistant. Antibiotic resistance occurs when bacteria change in a way that reduces the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. Thus the bacteria survives and continues to multiply, causing more harm.