One of the Reasons Scientists Have Had So Much Difficulty

question 10

Multiple Choice

One of the reasons scientists have had so much difficulty finding a cure for HIV/AIDS is that the HIV virus is quick to evolve resistance to the drugs used to treat it.What is the most likely mechanism for this type of evolution?

• A) Certain versions of the virus persist longer in the presence of a drug than others. Those viruses may survive drug treatment and pass their genes to their offspring.
• B) Every time an HIV drug is taken, it randomly kills off most but not all virus particles. Those that survive repopulate the body of their host.
• C) Although all copies of a particular strain of the HIV virus are identical, some are better at "hiding" in regions of the body that drugs cannot reach, and those viruses "teach" their offspring where to hide.
• D) Some versions of the HIV virus produce chemicals that break down the drugs before they can harm the virus.

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Definitions:

Load Factor

In transportation and logistics, it is the ratio of actual cargo carried to the total carrying capacity available, indicating efficiency in space usage.

Operating Expense

Costs associated with the day-to-day functioning of a business, excluding direct production costs.

Yield

The income generated from an investment, usually expressed as a percentage of the investment's cost or current market value.

Profit

The financial gain achieved when the revenues generated from business activities exceed the expenses, costs, and taxes needed to sustain those activities.