Respuesta :
3. Mountains and high plateaus protected the regional empires that included the four main river valleys of southeast asia.
4. Mountains and high plateaus encourage cultural diffution in the empires that arose in mainland southeast Asia.
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Answer:
3 & 4
Explanation:
Mountains and high plateaus protected the regional empires that included the four main river valleys of Southeast Asia.
Mountains and high plateaus made it difficult for the rest of Asia to trade with and conquer mainland Southeast Asia.