Which statement describes a core concept of natural selection?

• A. Variation exists among individuals
• B. All individuals have identical traits
• C. Traits acquired during life are inherited
• D. Environment never changes

Answer: (A)

Variation among individuals provides the raw material for natural selection. In any population, individuals differ in heritable traits that can affect survival and reproduction. When the environment favors certain traits, those individuals tend to survive longer and leave more offspring, so the advantageous traits become more common over generations. This is why having variation is essential for evolution to occur.

The other statements don’t fit because none of them reflect that essential starting point: if everyone were identical, there would be nothing for natural selection to act on. Traits that are acquired during a life aren’t reliably passed to offspring, so they don’t drive evolution. And environments do change, creating shifting pressures that influence which traits are favored.