Stabilizing vs. directional vs. disruptive selection
Infants of intermediate birth weight have the highest survival, and very small and very large infants have lower survival. This is:
Answer D: explanation for every choice
A
Directional selection favors one extreme.
B
Disruptive selection favors both extremes over the intermediate.
C
Sexual selection favors traits that improve mating success.
D
Correct. Stabilizing selection favors the intermediate phenotype and reduces variation.
TakeawayStabilizing: the middle. Directional: one extreme. Disruptive: both extremes.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb59.