Answer: The large land was isolated from much of the rest of the world by dry deserts to the north and west, the Pacific Ocean to the east, and impassable mountains to the south. This enabled the Chinese to develop independently from other world civilizations.
Explanation:
It could have been because their ammunition racks were protected by Water jackets, to prevent fires in the ammunition racks from spreading and potentially causing detonation
The answer is A, C & D make no sense. B is not wrong, but A is the better answer.
Building through the Sierra Nevada Mountains was very difficult and dangerous. Temperatures were freezing during the winter and in one year alone there were 44 storms.There was the great danger of an avalanche for the men working through 18 feet of snow and camping on the tunnels beneath it. Creating tunnels through the mountains required blasting with nitroglycerin. Advancing at one foot of mountain at a time, a total of 11 tunnels was created.