Osteoarthritis (OA) . OA is the wear-and-tear arthritis that usually occurs with aging or after injury. With OA, there's a wearing down of the cartilage that cushions the ends of the bones. OA causes joint swelling in those joints that bear weight over a lifetime, such as knees, hips, feet, and spine.
During the Zhou dynasty, the Chinese developed irrigation and flood- control systems. As a result, farmers could grow more crops than ever before. Because more food could support more people, the population increased. During the late Zhou dynasty, China's population had expanded to about 50 million people. Zhou people also learned to use iron, which was cheaper and stronger than bronze. Iron weapons, the catapult and China's first cavalry (military on horseback) were some of the Zhou achievements that helped strengthen the army.
The Shang dynasty period saw further strides in material culture, and some of the finest bronzes in world history were produced by Chinese craftsmen of the period. In due course, the Shang dynasty was succeeded by a new line of kings, of the Zhou dynasty. A Western Zhou bronze gui vessel. Reproduced under Creative Commons license 3.0. Under the early Zhou (or Western Zhou) the cultural and political reach of ancient Chinese civilization expanded enormously.