Answer :
Answer 1: According to the characteristics of the hydrography of the two countries the answer is Gobi Desert.
Answer 2: As for the information of Weather forcast from china, the answer of this question is 2b: Northern China
Answer 3: The history and geography studies of each country given above tell us more about it, so the answer is 3d, china expanded its long-age empire to include many regions.
Answer 4: the answer of the last question is the choice a: Members of the ethnic groups have different religious beliefs.