Correct option is B
Explanation -
The graph shows the distribution of bird bill lengths. Observing the pattern - The frequency of birds increases as bill length increases, with peak frequency at the longer lengths. This indicates that longer bills are being selected for — individuals with longer bills are more fit or have better survival/reproductive success. This is a classic case of directional selection, where one extreme phenotype is favored over others. The population mean shifts in one direction (towards longer bills in this case).
Incorrect options -
Option a - Neutral selection – Implies no selection pressure; traits vary randomly. Not supported by the clear trend in the graph.
Option c -Stabilizing selection – Favors the intermediate phenotype and reduces variation. The graph should show a peak in the middle — not at the extreme.
Option d - Mutational selection – Not a standard form of natural selection. Mutations may introduce variation, but the pattern here reflects selection pressure, not mutation alone.
Correct Option - Option b - Directional selection
