Question

AZT resistant virions may:

1) Decrease in the presence of AZT owing to natural selection.
2) Decrease as AZT is taken over time.
3) Increase in the presence of AZT owing to natural selection.
4) Increase if the AZT is removed from the patient's bloodstream.

Answer 1

AZT resistant virions may decrease in the presence of AZT owing to natural selection.Therefore, the most appropriate correct option is 1.

Step-by-step explanation:

The answer to the question is option 1) Decrease in the presence of AZT owing to natural selection. AZT (azidothymidine) is an antiretroviral drug used in the treatment of AIDS. However, over time, the HIV virus can develop resistance to AZT. This happens through a process of natural selection, where the virions that have mutations allowing them to survive in the presence of AZT are more likely to reproduce and increase in number. Therefore, the number of AZT-resistant virions would be expected to decrease in the presence of AZT, as the sensitive virions are killed off and the resistant ones become less prevalent.