Which factor most contributes to variation in population distribution in china, mongolia, and taiwan?
large chinese cities have millions of residents.

large chinese cities have millions of residents.

mountain ranges make much of the region too dry to farm.

mongolia is landlocked, and taiwan is an island.

china expanded its long-age empire to include many regions.

China, Mongolia, and Taiwan have population varieties because China expanded its long-age empire and included many regions. In the different dynasties that have ruled China, expansion of their empire was the main goal. It showed power and superiority above all. As a result of this, population diversity was common because of the constant migration of people from these different countries. That's why at present, they also tend to have similarities in their cultures, traditions, and beliefs.

The factor which mostly contributes to varition in the population distribution in China, Mongolia, and Taiwan would be that Mongolia is a landlocked country while Taiwan is an island and also that Mountain ranges make much of the region too dry to farm. These two factors strongly influence and have influenced in the past, how th edistribution of the population looked like. 

The answer is the third one or c