Answer:
1
Explanation:
The rest are wrong b/c it helped <em>expand</em> China rather than isolate it, they didn't use ships on the Silk Road, and it brought better communications, etc. between countries.
The answer is A. The main characteristic of a desert is its aridity. Most deserts receive an annual precipitation of ten or fewer inches. Temperatures can't be a defining characteristic of deserts because there are deserts with low temperatures such as those in the polar regions (antarctica). In these regions, water is unavailable because it is completely frozen as ice.
geophysical phenomena is earth and its environment in space for example its when earthquakes, Tsunami, Volcanic activity, cyclone stuff sorta like that
hope that helps