A compound is organic if it contains carbon covalently bonded to other atoms. Most often, the other atoms include hydrogen, oxygen, and/or nitrogen. A few carbon compounds, such as simple oxides (e.g. CO2) and cyanides (e.g. KCN) are excluded arbitrarily.
The Muscular system. If you look at the human body, you see we're made of layers. 1st layer is the skeleton, the maintains the body's shape, then you have the 2nd layer, the muscular, this provides the ability of movement. And the layers keep going until you get to the skin.
Answer:
If the activity of osteclasts(which demineralize bone) exceeded osteoblast activity(production of new bone), then the bone's mineral content(and thus its mass) would decline, making it weaker.