Answer:
It violated America's anti colonial principles.
Westward expansion routes
Marco Polo was an Italian merchant, explorer, and writer, born in the Republic of Venice. His travels are recorded in Livre des merveilles du monde, a book that described to Europeans the wealth and great size of China, its capital Peking, and other Asian cities and countries
Black holes themselves can not be seen, nor do they leave trails (since emptiness does not have to be caused by a black hole), but there is evidence for black holes: scientists can see the effects of their gravity on nearby stars. The answer is B.