Work Step by Step
D. is the opposite of B. the correct answer, and so can be eliminated, as can C. since mutations occur all the time, not just in the past. A. can be true but is usually not the case--most mutations are deleterious.
You can help us out by revising, improving and updating this answer.Update this answer
After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.