試題詳解

45. Within a few weeks of treatment with the drug 3TC, a patient’s HIV population consists entirely of 3TC-resistant viruses. What is the best explanation?
(A) HIV has the ability to change its surface proteins and resist vaccines.
(B) The patient must have become reinfected with 3TC-resistant viruses.
(C) HIV began making drug-resistant versions of reverse transcriptase in response to the drug.
(D) A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency. 
(E) Some viruses developed drug resistance and then passed their function.