1 Down syndrome, usually is caused by an extra copy of chromosome 21 (trisomy 21). Characteristics include decreased muscle tone, asymmetrical skull, slanting eyes and mild to moderate mental retardation.  Edward's syndrome, which is the second most common trisomy after Down syndrome. It is a trisomy of chromosome 18.
Guanxi describes the basic dynamic in personalized networks of influence, and is a central idea in Chinese society.
China is an East Asian country with a large territory, a huge population and an ancient history. With written records dating back 4,000 years, it is recognized as one of the four great ancient civilizations of the world, together with ancient Egypt, Babylon and India. Moreover, it is the only ancient civilization that has continued to this very day. China was one of the cradles of the human race.