Due to the high terrain, there is not enough heat in most areas. In the two photos (1 1 photo) of the Qinghai-Tibet Plateau above 4500m, the average temperature in the hottest month is less than 10℃(50℉), and there is no absolute frost-free period, so the seeds are difficult to mature, so they are only suitable for grazing. Grazing animals are mainly hardy cows, Tibetan sheep and Tibetan goats. Cold-tolerant varieties such as highland barley, wheat, pea, potato, round root and rape are the main varieties. Yarlung Zangbo River basin has low latitude and no severe cold in winter, so wheat can safely overwinter. Good lighting conditions, low temperature in spring and summer, and prolonged wheat growth period. The yield per mu of winter wheat in Lhasa reached a record 1.638 kg. In recent years, many hydropower stations, coal mines, steel mills, chemical plants and wool mills have been built on the plateau. New industrial cities such as Xining, Lhasa, Golmud, Linzhi and Shigatse have been continuously formed. At present, there are four highways: Sichuan-Tibet, Qinghai-Tibet, Yunnan-Tibet and Xinjiang-Tibet. The Qinghai-Tibet Railway was also opened to traffic. Civil aviation flights connect Xining, Golmud, Lhasa, Linzhi and Qamdo.