The respiratory system. The ribs form a cage around the lungs.
The skeletal, (or musculoskeletal) system supports the body. Parts of it, such as the rib cage also serve to protect vital organs.
To protect your lungs, heart and other vital organs
Your immune system and your rib cage, plus a layer of muscle
torso
To protect the lungs, heart and anything else important in there.
There are several: the ribs, the thoracic vertebrae and the sternum. Together they are called the rib cage.
The ribs are external to the heart
No
muscular
*
to protect your heart and lungs
bone