Which statement best describes gradualism?

• A. Large changes occur suddenly
• B. Small changes accumulate gradually over time to produce large differences
• C. Changes occur only due to genetic drift
• D. Changes occur rapidly in response to catastrophic events

Answer: (B)

Gradualism is the idea that evolutionary change happens through many small, incremental differences that accumulate across generations, so that over long periods these minor changes add up to big differences in form and function. This is why the statement describing small changes accumulating gradually over time to produce large differences is the best fit. Over generations, small mutations and variations can be acted on by natural selection, and their cumulative effect can lead to substantial differences between species. The other scenarios describe different patterns of change: large changes appearing all at once, change driven only by genetic drift, or rapid shifts after catastrophic events, which are not what gradualism emphasizes.