Which of the following directly led to the american civil war

Kublai khan honored his mongol heritage by: a)marring only one wife b)praying facing mecca five times a day c)slaughtering ten chinese officials every year d)building a large enclosed hunting ground at shangdu,his summer palace

What event started the space race and made americans feel their security was threatened a.) alan shepard's suborbital flight. b.) the launch of sputnik c.) the launch of explorer d.) the cuban missle crisis

In a few sentences, explain how the medici family contributed to the renaissance.