what are the ethnic groups belonging to this country?
The Han Chinese, Tibet and Xinjiang.
China
 The Han Chinese – the world's largest single ethnic group – outnumber other ethnic groups in every provincial-level division except Tibet and Xinjiang. 
what is  xixiasaurus? It is a genus of troodontid dinosaur that lived during the Late Cretaceous Period where was it found? Xixia County, Henan Province, in central China. which family of classification did he belong to? troodontid dinosaur when was it discovered? UNANSWERABLE which biological system is it related to? UNANSWERABLE how is palaeobiology related to this? They stated that troodontid anatomy was consistent with a carnivorous lifestyle, and pointed out that the structure of their serrations was not much different from those of other theropods. which is an environment related to this theropods? It is known from the mid-lower part of the Majiacun Formation of China, which dates to the Late Cretaceous period, but there has been disagreement about the exact geological age of the formation. which early dynasty ruled this country? The first dynasty was the Xia, which emerged around 2100. when did it become people's republic? On 21 September 1949
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China [SEP] Ethnic groups
China legally recognizes 56 distinct ethnic groups, who altogether comprise the "Zhonghua Minzu". The largest of these nationalities are the ethnic Chinese or "Han", who constitute more than 80% of the total population. The Han Chinese – the world's largest single ethnic group – outnumber other ethnic groups in every provincial-level division except Tibet and Xinjiang. Ethnic minorities account for about less than 25% of the population of China, according to the 2010 census. Compared with the 2000 population census, the Han population increased by 66,537,177 persons, or 5.74%, while the population of the 55 national minorities combined increased by 7,362,627 persons, or 6.92%.