Have you ever tried to be perfectly still for just one minute? Try as you might, you just can't do it. Somewhere in your
body,certain muscles are always working. For example, muscles continuosly push blood though your blood vessels. A muscle makes
you breathe. And musles hold you upright. If all your muscles rested at the same time, you would collapse. Your muscles are
made of muscle tissue and connective tissue. Muscles that attach to bones and the connective tissue that attaches them make
up the muscular system!