Which statement best describes natural selection?

• A. All individuals have equal chances of survival.
• B. Variation leads to differential survival and reproduction.
• C. Survival is completely random.
• D. Evolution occurs without any variation.

Answer: (B)

Natural selection is the process by which heritable variation in a population leads to some individuals being more likely to survive and reproduce than others. When certain traits give an advantage in a given environment, individuals with those traits leave more offspring, passing those traits on. Over many generations, the frequency of favorable traits increases, shaping the population. This isn’t random survival—it's guided by how well traits help organisms cope with their surroundings, and it requires variation that can be inherited.

The statement that best describes this is that variation leads to differential survival and reproduction. It captures the essential link between how differences in traits influence who survives and who reproduces, driving evolutionary change. Options claiming equal or random survival or evolution without variation don’t reflect how natural selection works in shaping populations.