I found a great site that will answer your homework question (but you really should have googled it- the answer is easily found!) Humans are vertebrates, animals having a vertabral column or backbone. They rely on a sturdy internal frame that is centered on a prominent spine. The human skeletal system consists of bones, cartilage, ligaments and tendons and accounts for about 20 percent of the body weight. The living bones in our bodies use oxygen and give off waste products in metabolism. They contain active tissues that consume nutrients, require a blood supply and change shape or remodel in response to variations in mechanical stress. Bones provide a rigid frame work, known as the skeleton, that support and protect the soft organs of the body. The skeleton supports the body against the pull of gravity. The large bones of the lower limbs support the trunk when standing. The skeleton also protects the soft body parts. The fused bones of the cranium surround the brain to make it less vulnerable to injury. Vertebrae surround and protect the spinal cord and bones of the rib cage help protect the heart and lungs of the thorax. Bones work together with muscles as simple mechanical lever systems to produce body movement. Bones contain more calcium than any other organ. The intercellular matrix of bone contains large amounts of calcium salts, the most important being calcium phosphate. When blood calcium levels decrease below normal, calcium is released from the bones so that there will be an adequate supply for metabolic needs. When blood calcium levels are increased, the excess calcium is stored in the bone matrix. The dynamic process of releasing and storing calcium goes on almost continuously. Hematopoiesis, the formation of blood cells, mostly takes place in the red marrow of the bones. In infants, red marrow is found in the bone cavities. With age, it is largely replaced by yellow marrow for fat storage. In adults, red marrow is limited to the spongy bone in the skull, ribs, sternum, clavicles, vertebrae and pelvis. Red marrow functions in the formation of red blood cells, white blood cells and blood platelets. http://training.seer.cancer.gov/module_anatomy/unit3_1_bone_functions.html

I expect one is to get a backbone. :) Do your own homework.

Ah yes, you wouldn't know that. Plant life gets along without skeleton.

One of them is to hold you upright as you do your own homework.

I'd like to put in that I do not know why you have negative points, this is a good question. Well, I know that it is for structure, support, protection, I think movement( that may be muscles).

Hmmm.. I think I have answer to this question. 1.Bones give shape to our body. 2.Bones, togather with muscles, help us in movement. 3.Skeletal system provides protection to many of the soft internal organs, reducing risk of injury to them. For example, brain in the skull, vertebrae protect spinal cord, ribs protect heart and lungs. 4.Blood cells are produced in the bones, e.g, red blood cells are produced in femur. 5.Bones store several minerals including calcium and phosphorus. When required these chemicals are released into blood, facilitating the balance of minerals in the body.