14. C. Global Warming
almost 99 persent of the mass of the human body is made up of six elements oxygen, carbon, hydrogen, calcium, phosphorus. Only about 0.85 persent is composed of other five elements: potassium, sulfur, sodium, chlorine, and magnesium.
The circulatory system, also called the cardiovascular system or the vascular system, is an organ system that permits blood to circulate and transport nutrients (such as amino acids and electrolytes), oxygen, carbon dioxide, hormones, and blood cells to and from the cells in the body to provide nourishment and help in fighting diseases, stabilize temperature and pH, and maintain homeostasis.