The answer would be He paid them for their land
The Gadsden Purchase enabled the United States to "B. Increasecrop production in the Southwest," since this was a purchase of relatively fertile land in the region.
As noted by the other Brainly user's response here, early Chinese civilization developed between the Yangtze River and the Huang He River (or Yellow River), because the plain between the rivers is fertile, allowing for the development of agriculture. It's also worth noting that the these two rivers extend for hundreds of miles from west to east before reaching the sea. This facilitated trade and transportation on the rivers. It also allowed Chinese rulers to maintain control and communication across the wide expanse of main Chinese territory.
Also worth noting would be the mountains and deserts and ocean that set China off from other lands. Large mountain ranges exist in the south and west regions of China -- such as the Himalayan Mountains, Kunlun Mountains, and Tianshan Mountains. The Gobi Desert sits in the northern part of China, and the Pacific Ocean is to the east. These various geographic features set China off from other lands, so that civilization there developed in its own unique ways, apart from outside influence.
Answer:
2.5 million kelvins
Explanation:
The data revealed X-rays from these distant sources are absorbed selectively by oxygen ions in the vicinity of the galaxy. The scientists determined the temperature of the absorbing halo is between 1 million and 2.5 million kelvins, or a few hundred times hotter than the surface of the sun.
