30 dogs have bellybuttons? if not then how did they get air food and nutrition?

Yes they do. The belly button is the scar left by an umbilical cord, and dogs, like most mammals are born with umbilical cords. When dogs are born, their cords are still attached to the placenta, and the mother chews it off and usually eats it. Which is really gross.

running

dancing

jumprope

walking

streching

jogging

hop scotch

swimming

riding your bike

skating

sit ups

push ups

crunches

sorry there were no options posted so i listed a bunch of workout activiteis

answer(b) keep oxygenated and deoxygenated blood separate;