What has occurred when natural selection results in a shift toward one end of a normal range of traits? 

A)  directional natural selection 
B)  diversifying natural selection 
C)  stabilizing natural selection 
D)  discontinuous natural selection

Directional Natural Selection

A process where natural selection favors one extreme phenotype over others, causing a shift in the population's genetic variance.

Shift

A change in position, direction, or tendency, often indicating a transformation in conditions or strategies.

Traits

Traits refer to distinguishable characteristics or attributes of organisms, which can be physical, such as color and size, or behavioral.