Which of the following is not true?
A. Humans rely entirely on technological adaptations in order to thrive in various environments and they do not exhibit biological adaptations.
B. All humans living today belong to a single species.
C. Humanity cannot be classified into discrete, bounded geographic categories because variation in most traits exists along clines.
D. Ecological and social environments lead to biological differences between individuals.
E. Biological differences across human populations are in part due to biological adaptations to local environments.