Answer:
They caused a great deal of attention as America and the U.S.S.R were behind the scenes with both sides pouring in many resources. Both sides were looking for the promotion of communism or democracy, with both sides believing that the other was looking for world domination.
Explanation:
https://study.com/academy/lesson/how-geography-isolated-ancient-china.html
That video will explain everything. I have already learned this in school, and it is very important on the test. VERY IMPORTANT.
I am guessing but im not sure i think the answer is humidity