I don’t think 2021 will be better LOL
Answer:
coal mills and new inventions like the train that needed coal to power the engine, and the steam pressure was from the coal burning. that's why it's called a steam train .
Answer:
Becuase of the issue of more slave or free states. If one Slave State outnumbered the Free states would get most of the vote on something. That Free states may not want.
With the new states/land being in the issue of the balance of free states and slave states.
B is the correct answer, The Xia dynasty was the one not to believe had existed
