Why Haven't Humans Evolved a Resistance to the Common Cold

question 52

Multiple Choice

Why haven't humans evolved a resistance to the common cold?

• A) Colds are effectively killed by antibiotics, so there's no need.
• B) Cold viruses haven't been in existence long enough to exert selective pressure.
• C) Colds are not serious enough to remove nonresistant variants from the population.
• D) We could evolve resistance if we stopped taking so many over-the-counter medications for colds.

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The cost that varies with each unit produced, including direct materials and labor, but does not include fixed costs.

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The percentage of a property's assessed value that is charged as tax by local governments to fund public expenses.

Break-even Point

The sales level at which total revenues equate to total costs, resulting in no profit or loss, indicating the minimum sales necessary to cover all expenses.

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