Question

4 mutations that result in resistance to specific antibiotics mutations that result in resistance to specific antibiotics in bacterial organisms occur multiple choice only when the bacteria are exposed to the drug to which they become resistant more often when the bacteria are exposed to the drug only when the bacteria are exposed to radiation or other mutagens at any time, even when the bacteria are not exposed to the drug

Explanation:

Bacterial mutations can occur spontaneously at any time due to errors in DNA - replication. Exposure to antibiotics selects for pre - existing resistant mutants rather than causing the mutations. So mutations for antibiotic resistance can happen even without drug exposure.

Answer:

D. at any time, even when the bacteria are not exposed to the drug