Which of the following terms is associated with natural selections?

Step 1: Analyze the question The question asks which term is associated with natural selection, the mechanism of evolution proposed by Charles Darwin.

Step 2: Explain the concept Natural selection is the process by which organisms with traits better suited to their environment survive and reproduce more successfully than others. Over time, the favourable traits become more common in the population. The key ideas are:

• Variation exists within a population.
• More offspring are produced than can survive (competition).
• Individuals with favourable traits survive and reproduce.
• These traits are passed to the next generation.

Step 3: Examine each option

• A. Adaptive radiation: The diversification of a single ancestral species into many species that fill different niches (e.g., Darwin's finches). It is a result of evolution, not a term that defines natural selection.
• B. Differential reproduction: Natural selection does act through differences in reproductive success, so this is closely related. It is, however, a more technical description of the outcome than the classic term.
• C. Population variability: Variation is a necessary raw material for selection, but it is not the term for the process itself.
• D. Survival of the fittest: The phrase popularly and classically linked to natural selection. Herbert Spencer coined it, and Darwin adopted it to describe how the best-adapted individuals survive and pass on their genes.

Step 4: Identify the answer Option B is arguably also valid in modern biology, but in the WASSCE context the term most directly and traditionally associated with natural selection is "Survival of the fittest".

Tip: In WASSCE, match the phrase to its classic pairing:

• Natural selection → Survival of the fittest
• Adaptive radiation → Darwin's finches / diversification
• Use of and disuse → Lamarck

Remember that "fittest" means best adapted, not necessarily strongest.