In Darwinian natural selection, which statement is true?

• A. Some individuals have traits that give them an advantage in reproduction.
• B. All individuals have identical fitness.
• C. Variation is completely random and not influenced by environment.
• D. Species are immutable.

Answer: (B)

Natural selection works because there is heritable variation in traits within a population, and the environment favors those traits that improve reproductive success. Individuals with advantageous traits tend to leave more offspring, so these traits become more common over generations, leading to adaptation.

That idea matches the statement that some individuals have traits that give them an advantage in reproduction—the essence of differential reproductive success driving evolution.

The other statements don’t fit: fitness is not identical across individuals; it depends on the trait and the environment. Variation arises in part randomly, but selection is not random—it favors traits that work best in a given environment. And species are not immutable; populations change over time through evolutionary processes.