1 Construction started on the Great Wall of China in 200 BC. In 1639 Shoguns closed Japan to the world. Ok. In 1854 Japan opens its ports to foreign trade.
2 The relative location of the North China plain is very close to the Yellow Sea, East China Sea and South China Sea. The largest area was brown, which meant 7000 feet above sea level.
3 Sloping land is terraced so when it rains the water is distributed evenly and not just gushed down onto the poor little plants. IT also holds the soil in place so that farmers can plant crops without worry about sliding down in mud and disgrace.
4 What factors contributed to the diversity of religion in China? The same thing as with in any other country. War, violence, leaders who think they can tell an entire nation what to believe and the people who go down without a fight AND the ones who do.
Buddhism influenced China very strongly. Its leaders liked Buddhism. The people liked the leaders. And thus Buddhism almost became one with china.
Important factors to include: China is a large region with many dialects and diverse
cultures. Such an environment makes often people more open to different ideas.
5 Tea was spread by normal means of transportation. Little Asian dudes on flying dragons, broomsticks and sports cars. Or by sea, by terrible journeys across land and rough terrain.
The Chinese probably traded tea for other goods with neighboring nations. As these nations developed land and sea trade routes with other, more distant nations, the use of tea spread to ever more remote locations and eventually, to Europe and the Americas.
6 The civil service system strethneged China. Under the system, officials gained jobs through merit, not by birth or wealth. Also the Confucian-educated officials shared the same values and traditions. The common bond helped to unite the vast empire and hold it together as dynasties chained. This system of choosing officials lasted until the early 1900.