Humans are often called the naked apes Since we have extensive hair follicles all over our body why do you suppose we lack body hair?

Answer 1

The most widely held theory is that humans lost their hair evolving on the savannas of Africa in order to stay cool.

One controversial hypothesis, called the Aquatic Ape Hypothesis, suggests that humans lost their hair evolving in semiaquatic or shoreline areas of East Africa as an adaptation to water (cf. dolphins and whales and their hair patterns).
its a genetic thing. From birth little particles of hair will start growing all over your body. As you get older the hormones in your body start to increase and more hair is produced.

Answer 2

One theory is that humans lost most of their body hair during the course of evolution as a way to regulate body temperature more efficiently. This allowed our ancestors to engage in endurance running activities, as reduced hair allowed for better heat dissipation while running. Additionally, the loss of body hair may have had social implications related to communication and the use of clothing for protection and adornment.