Compared with the last glacial period of 26,000 years to 16,000 years ago, the desert in the northern region of China has shrunk considerably, and it has expanded significantly compared to the Holocene Warm period from 9000 to 5,000 years ago. Therefore, researchers believe that Changes in climate, and even changes in the amount of ice in the high latitudes of the northern hemisphere, are the main factors affecting the change in the surface environment of deserts and sandy lands in China. If the following are true, the above argument can be strengthened most:. ['The use of biological and engineering measures to build a protective system helps control desertification.', 'A crescent-shaped dune is formed in a dry area in the northwest due to wind all year round.', 'The Sahara Desert is located on both sides of the Tropic of Cancer, controlled by the subtropical high pressure zone, and the climate is hot and dry.', 'During a period of time, the temperature in northern China increased, rainfall increased, and the area of quicksand shrank by half.']