Question

which of the following is the best description of a mutation and its role in evolution? mutations are changes in dna that lead to decreased genetic variation in populations. mutations are random changes in dna sequences that can lead to the generation of new alleles. mutations are random changes in dna sequences that usually lead to monstrous outcomes for the organism. mutations are changes in dna that occur in response to environmental challenges.

Explanation:

• First option: Mutations increase (not decrease) genetic variation. Eliminate.
• Second option: Most mutations are neutral or beneficial, not "monstrous". Eliminate.
• Third option: Mutations are random DNA changes that can create new alleles, a key source of genetic variation for evolution. Correct.
• Fourth option: Mutations are random, not a response to environment. Eliminate.

Answer:

Mutations are random changes in DNA sequences that can lead to the generation of new alleles.