Stabilizing selection tends to favor which type of trait values?

• A. Extreme values
• B. Both extremes
• C. Intermediate values near the center
• D. Very high variance

Answer: (C)

Stabilizing selection favors intermediate trait values because individuals with average, or near-average, phenotypes tend to have higher fitness than those at the extremes. This environmental filter means extreme trait values are selected against, and the population’s traits stay centered around the mean with less variation over time. A classic example is human birth weight: babies around a normal weight have better survival and health outcomes, while those that are too small or too large face greater risks. So the trait values cluster near the center rather than at the ends, reflecting a reduction in variation.