Functions:
The Skeletal system wouldn't exist, unless it had some essential functions. The most well known of these is that it provides shape and support, the size and shape of your bones define the size and shape of you. Bones are so strong that they are the only thing that can keep you upright. The second most well known function, is that it protects organs. Since bones are so strong, humans have evolved to use them as protection for organs like the heart, lungs, and brain. The third most well known function is movement. Without bones, muscles would only have floppy tissue to connect to, bones give muscles a beam to connect to, to be able to move more flesh. A not so commonly well known function of bones is that they store certain materials. For instance, the insides of bones contain marrow, yellow marrow will contain fat, while red marrow will contain red blood cells. A final function of bones, are that they produce red blood cells. Bones give off red blood cells when they are needed. When the bones don't have blood cells left, the red marrow turns to yellow marrow.