Why did international trade lead to the spread of the Bubonic Plague? A. Trade weakened the economy and prevented research to cure the plague.
B. Trade isolated communities and allowed the plague to spread faster.
C. The plague infected many people who used or lived along trade routes.
D. The plague forced people to trade for resources in order to survive.

C, plague was likely spread through Eurasia via these trade routes by parasites carried on the backs of rodents.

how do you know that

explanation:

two jet streams that directly affect the formation of weather in the continental part are a polar jet and a subtropical jet. they are responsible for the transportation of weather systems, which directly affect people. the polar front is the boundary between cold air from the north pole and warmer equatorial air. both the polar jet and the subtropical jet blow from the west to the east, and follow the boundary between cold and warm air.

the strongest jet streams are polar jets, while subtropical jets are somewhat weaker.

the right answer is c. the polar jet stream is generaly stronger than the subtropical jet stream.