Cardio is heart, because you heart pumps blood to the organs, tissue, and cells of your body.
The heart is an example of an organ or a muscle.
Hope i helpedXD <span />
The hamstring, Bi-flexes, hip muscles, Abbs, thigh muscles. Please award Brainliest, if it weren't for it then i would be at expert, but i only need 3 more for Virsito.