The third step of the staircase

The bulk of China’s population lives in in the third or lowest step down the starcase, east of the line from the greater Hainggan, Taihang and Wushan ranges and the eastern rim of the Yunnan-Guizhou Plateau to the sea coast. Here are hills less then 1,000 metres and plains less then 200 metres in elevation. Lying from north to south are the northeast plain the north China Plan, the Middle-Lower Changjiang Plain and the hills and foothills south of the Changjiang River. With superior geographical conditions and a large concentration of big cities of China.
To the east of the third step in the continental shelf formed by the shallows, which are an extension of the land in to the ocean.The third step of the staircase