why do east and south Asia form a region ? A. the earliest civilizations developed along the Indus and yellow river valleys in India and China B. For thousands of years Asian civilizations were separated from European and Africans C. they have the same forms of government D. they both have natural barriers like the Himalayas

B.For thousands of years Asian civilizations were separated from Europeans and Africans.

Explanation:

The region of eastern and southern Asia was separate from Europe for most of history, and developed its own distinct civilizations and ethnic groups. Being far from western Asia, they were never subjugated by the developing Mediterranean empires.

Also,

They both have natural barriers like the Pacific Ocean that isolate them from other regions.