Use the Following Information to Answer the Questions Below

question 19

Multiple Choice

Use the following information to answer the questions below.
HIV's genome of RNA includes code for reverse transcriptase (RT) , an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR) , an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR.
-Which is a True statement concerning genetic variation?

• A)It is created by the direct action of natural selection.
• B)It arises in response to changes in the environment.
• C)It must be present in a population before natural selection can act upon the population.
• D)It tends to be reduced by the processes involved when diploid organisms produce gametes.
• E)A population that has a higher average heterozygosity has less genetic variation than one with a larger average heterozygosity.

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Definitions:

Fossil Record

The accumulation of evidence from preserved remains or impressions of organisms from past geologic ages.

Background Extinctions

The normal rate of extinction for species or a certain baseline level of extinctions that occurs without human intervention or major catastrophes.

Genetic Mutations

Changes in the DNA sequence of an organism's genome, which can result in variations in physical appearance, function, or behavior.

Artificial Selection

The human practice of breeding plants or animals for desired traits.