Answer:
The Geography of China helped keep the areas that they lived in safe through environmental means, (such as having natural defenses as the likes of rivers, mountains, etc. The area also was part of the Yellow River Region, which had a annual overflow of it's banks, leading to a deposit of nutrient-rich soil called "silt". Silt was essentially used for farming, which allowed the Chinese people to settle there (Farming = food, which is needed by humans). The Mountain areas also served as a means of protection from foreign invaders, but also limited access to other nations. This made naval navigation more reasonable, and led to the Chinese civilization to build large navies for exploration, military usage, etc. (though it was destroyed in China's age of Isolation.)
China was built on a land made to build civilizations. It had everything needed for a civilization to flourish: Source of water, Nutritious soil, Natural protection, Reasonable climate, etc. Without these needed material, civilizations would not flourish.
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