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.
This introduction to the African contributions to science, technology and development begins with the dawn of civilization and the domestication of agriculture, which introduced crops that have long continued to be important in food production.ollective Volume The Slave Route Project, UNESCO 10 contribution of Africa in the evolution of the ancient world into the modern world. A focus on technological and agricultural innovations establishes that skills acquired in Africa could be transferred to the Americas and therefore could affect development.