Please help me I don't undertand

Which of these was an accomplishment of the han dynasty? the invention of the seismograph finding a water passage to europe the invention of the ballpoint pen the invention of the abacus

Choose the option that best completes this statement: the british and the continental system were blockades that prevented the united states from trading with without extreme risk to ships, goods, and sailors.

Ahistorian who compares the expansion of political systems to the expansion of economic systems is organizing history by