During which decade did transcontinentral rail service begin in the United States?

Idon't really understand the question. it counts for 20% of my lesson grade and i really need putting the answer into words. anything will . i need asap so im awarding 30 points. a disagreement between states of the united states concerning the rights of states vs. the authority of the national government led to the civil war. state governments were forced by war into a subservient position. what might happen if national governments ceded their authority to a world government by international treaty?

Which of the four planes was hijacked first? a. flight 175 b. flight 77 c. flight 11 d. flight 93

Why did trade along the silk road increase after it fell under mongol control? o people stopped using camels the mongols paved the road o it became safer to travel the mongols were better traders next question ask for