How do muscles form?

In the human body there is around 650 muscles that we have in the body. Muscles work every time you move, even if your exercising or even sleeping. Although we cannot see our muscles, we know by the outer shape that they are there. Muscles are a lot of fibers tied together and this is called a the motor unit. If you have more fibers this means you have more muscles and will be able to lift more. The more you expand your fibers the stronger you will be. Most muscles work in pairs but not all and also your muscles move your bones around so every time you break a bone you are also damaging you muscles that could cause long time injury. For example the biceps and triceps work together to help perform whatever task your arm does. In conclusion muscles are formed by fibers all over the body.