d) Although there are other mammals that are hairless, humans are the only primates to have mostly naked skin.
a) Humans evolved that way because changes in the climate 200,000 years ago that demanded that they travel long distances for food and water.
b) Humans also have an abundance of sweat glands, called eccrine glands.
c) To make these glands more efficient, human bodies had to lose their hair to better dissipate heat.
e) This enabled them to obtain the food they needed to nourish their bodies and brains, while keeping them at the right temperature and allowing them to grow.
