Natural selection drives evolutionary change through survival advantages

Steps:

• Lizards show variation in leg bone length within the population.
• Longer legs enable better climbing and predator escape, increasing survival.
• Shorter-legged lizards face higher predation and die out over generations.
• Surviving longer-legged lizards reproduce, shifting the population trait.

Why A is correct:

• Natural selection occurs when heritable traits enhancing survival and reproduction become more common, as defined by Darwin, matching the predator-driven adaptation here.

Why the others are wrong:

• B. Extinction: Refers to complete species disappearance, not trait shift in a surviving population.
• C. Conservation: Involves human efforts to protect biodiversity, unrelated to this natural process.
• D. Artificial selection: Human-imposed breeding for desired traits, unlike this predator-influenced change.

Final answer: A