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.
Answer: See below
Explanation:
p-(p+20) = 4(p-5) + 3p
p-p-20 = 4p - 20 + 3p
-20 = 7p -20
40 = 7p
40/7 = p
Only one president, <u><em>Woodrow Wilson</em></u>, had a doctorate, and was president of Princeton University before becoming the U.S. President.