Core Effects of Natural Selection Steps:

• Natural selection favors reproduction of better-adapted individuals, increasing their prevalence in populations.
• In changing environments, if no suitable adaptations exist, less fit individuals die out, potentially causing species extinction.
• Gene mutations occur randomly and independently, providing variation for selection to act upon, but selection itself does not induce mutations.
• Evaluate options by matching statements to these principles: true for adaptation survival, true for extinction possibility, false for causing mutations.

Why A is correct:

• Matches Darwin's theory of natural selection as differential survival acting on existing variation, promoting adaptation while allowing extinction without generating mutations.

Why the others are wrong:

• B: Errs by denying extinction (selection can eliminate unfit species) and claiming it causes mutations (mutations are spontaneous).
• C: Wrongly rejects adaptation survival, which defines natural selection.
• D: Falsely dismisses both adaptation and extinction benefits while affirming mutations.

Final answer: A