1) The word "vassal" was mostly used for the knights who were responsible for providing the military defense for the king - the answer is "perform military service"
2) Magna Carta is known as the first document to limit the power of the king ! (3rd option)
3) this was the Holy Roman Empire, which was actually an association of independent states.
Mass = force/acceleration
Mass = 6.0/3.0
Mass = 2kg
They were two of the richest, most powerful men in America during the Gilded Age.
I believe the answer would be France and the Soviet Union.
