What Are Two of the Primary Sources of the Variability

question 74

Multiple Choice

What are two of the primary sources of the variability that is necessary for natural selection to occur?

• A) competition and fission
• B) competition and heritability
• C) heritability and sexual recombination
• D) mutation and sexual recombination

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Definitions:

X-Linked

A gene carried on the X chromosome. If a male inherits an X-linked recessive trait from his mother, he expresses that trait because the Y from his father has no counteracting gene. Females are more likely to be carriers of X-linked traits but are less likely to express them.

Epigenetic

The study of heritable changes in gene expression that occur without alterations in the DNA sequence, influenced by environmental factors.

Polygenic

Pertaining to or involving multiple genes, especially in relation to the genetic basis of complex traits and characteristics.

Nonadditive

A property or situation in which combining two substances or quantities does not simply result in the sum of their individual effects.