A 'Geographic Cline' Is Generally Defined as A

Multiple Choice

A 'geographic cline' is generally defined as a:

A) decrease in fitness across a geographic region.
B) incremental spatial (regional) gradient in the distribution of a human biological trait.
C) type of climate change brought about by overuse of ecological resources.
D) valley in which early human remains are likely to be found.
E) migration route for early humans.