What is the role of mutation in evolution?

• A. Mutations decrease genetic variation.
• B. Mutations create new alleles; selection changes allele frequencies over generations.
• C. Mutations eliminate selective pressure.
• D. Mutations only occur in noncoding DNA.

Answer: (B)

Mutations introduce new genetic variation by creating new alleles. This variation is the raw material on which evolution acts. Natural selection acts on these differences, favoring alleles that improve survival and reproduction, which changes allele frequencies in a population over generations. Over time, these changes accumulate and lead to evolution. The other statements aren’t accurate: mutations don’t decrease variation, they create it; they don’t eliminate selective pressure, they provide the material selection works on; and mutations occur in both coding and noncoding DNA, not only in noncoding regions, with effects that can be neutral, beneficial, or harmful.