Plants and animals help keep the soil fertile. Plant roots tunnel through the soil and break it up, and decaying plants form humus. Burrowing animals mix the soil; the excrete of animals contribute nutrients and improve soil structure.
Chinese medicine is a system of medicine partly based on the idea that an energy, called qi (say chee), flows along pathways in the body called meridians. In this belief, if the flow of qi along these meridians is blocked or unbalanced, illness can occur.
Internal medicine. Internal medicine or general medicine (in Commonwealth nations) is the medical specialty dealing with the prevention, diagnosis, and treatment of adult diseases. Physicians specializing in internal medicine are called internists, or physicians (without a modifier) in Commonwealth nations.