Final answer:
Traits that die off during selection can be extreme or moderate, depending on stabilizing, directional, or disruptive (diversifying) selection, with stabilizing selection selecting against extremes, directional selection favoring one extreme, and disruptive selection favoring both extremes while selecting against moderate phenotypes.
Step-by-step explanation:
The traits that are more likely to die off during selection are traits that were too extreme or too moderate, depending on the type of selection. In stabilizing selection, extreme phenotypes are selected against, which narrows the range of variation. This is observed, for example, in human birth weights, where very large or very small babies at birth are less likely to survive. In directional selection, one of the extreme phenotypes is favored, leading to a shift in the distribution toward that extreme, as seen in the beak size of Galápagos finches.
On the other hand, disruptive selection, also known as diversifying selection, favors individuals at both extremes of the phenotypic distribution while selecting against moderate phenotypes. This occurs in cases such as sexual dimorphism or the multiple male forms in animal populations, where extremely large alpha males dominate and very small males sneak copulations, but the medium-sized males are selected against.