humans have a lot of homologous structures in common with other animals, and several of these structures are no longer in working order in human bodies. These non-functioning structures are called vestigial structures. They still show evidence of common ancestry, but they do not do the same thing in humans as they do other animals.
Listed below are mostly vestigial structures. Select the one that serves a purpose in humans.
a. pelvis: supports upper body and attaches to lower body in humans versus being tiny and nonfunctional in leg less animals like whales and snakes
b. ear muscles: ability to wiggle ears in humans versus rotating ears to hear predators and prey animals like deer and rabbits
c. hair raising: goosebumps in humans versus raising hackles to appear larger and aggressive in other animals like cats and monkeys
d. tail: tail bone in humans versus long tails or balence and communication in other animals like lizards and wolves