Which of the following has NOT been shown to follow or exhibit a geographic cline, at least historically (prior to frequent travel and relocation)?

Question

Quizplus · Accepted Answer

While genetic factors may contribute to athletic prowess, there is limited evidence to suggest that this exhibits a geographic cline. Instead, athletic performance is largely due to factors such as training, nutrition, and access to resources. The other choices, ABO blood group distribution, sickle cell trait, ability to digest lactose as an adult, and skin color, have all been shown to exhibit geographic clines historically.

Which of the Following Has NOT Been Shown to Follow