People have a little pink band in the inside corner of their eye. "This is the plica semilunaris," says Dorsa Amir, an evolutionary anthropologist. "It used to be a third eyelid that would blink horizontally." Amir posted a fascinating Twitter thread of other " evolutionary leftovers that no longer serve a purpose" in the human body.
Did you know the human body is full of evolutionary leftovers that no longer serve a purpose? These are called vestigial structures and they're fascinating. (1/8)
— Dorsa Amir (@DorsaAmir) January 15, 2019