Your most important bits

My children were discussing which is the most important bit of the body.

If your brain just disappeared you would die instantly. Or you would at least fall over.

If your lungs vanished, would you die instantaneously, or would it take as long as you can hold your breath for?

But then there's your feet. Without them, you wouldn't be able to go anywhere.

Ah-ha, but snakes don't have feet!