Question

in the given graph, the taller the curve, the higher the fitness. in looking at the \after\ (blue) curve, what type of selection has been shown to occur?
declining selection
directional selection
stabilizing selection

Explanation:

Directional selection favors one extreme phenotype. If the "after" (blue) curve is taller (higher fitness) at one end of the trait spectrum (assuming from the context of the graph - though graph not fully visible but based on the options and knowledge of selection types), it indicates directional selection. Declining selection is not a standard term in evolutionary biology selection types. Stabilizing selection favors the intermediate phenotype (curve would peak in the middle and be shorter at extremes).

Answer:

directional selection