What is directional selection and how does it affect phenotype distribution in a population?

• A. A selection that favors one extreme phenotype, causing a shift in the population average.
• B. A selection that favors both extremes, leading to a bimodal distribution.
• C. A selection that favors intermediate phenotypes, reducing variation.
• D. A selection that randomly favors different phenotypes at different times.

Answer: (A)