I know one of the answers are "the fingers of the wool pluckers would be eaten by the acid that was used to loosen the wool and pulled off by bare hands"
But I am not sure what the other two are, if you get them please let me know.
Answer:
The Yellow River's Contribution to the World
Gunpowder, the compass, paper making, and printing - all of these inventions not only promoted Chinese cultural development, but also spread to the rest of the world, making an important contribution to the development of humankind.
Answer:
The size of the empire made it hard to defend.
