The reasoning given for the traits is probably the second hand version of an off-handed conjecture of a TA in an intro level Anthropology course. At the same t

The reasoning given for the traits is probably the second hand version of an off-handed conjecture of a TA in an intro level Anthropology course. At the same time, if the traits are found in a large part of the population (50%?) the cause for their selection could very easily be related to acquiring food.