A scientist has observed animals in a particular habitat for some time. She notices that the slower gazelles tend ti fall victim to predators more frequently than faster ones. Over time, she notes that the gazelle herd on average runs faster. She is observing
A - Disruptive selection
B - Directional selection
C - Balanced polymorphism
D - Heterozygote advantage
Answer: B - Directional selection
DIRECTED SELECTION is a type of natural selection in which individuals with a trait at one end of a phenotypic spectrum are most fit.