Respuesta :
Monkeys and humans share a common ancestor. ... The tailbone became vestigial, and the tail disappeared because humans could balance on two legs. 3. Grabbing things with their tails became difficult for humans, so their tails disappeared.
hope dis helps ^-^
Even tho we share common traits humans could balance on two feet so over time the tail became useless which leads to evolution or genetic mutations to adapt to the new environment or changes