Each Mayan city had a king. The king was usually hereditary. The king used his power and wealth to support the nobles. The nobles served as officials and such in the kings administration. The nobles were loyal to the king because he ensured their legitimacy and the king got help in running things from nobles. All right there you go. Hope this is enough and it helps.
The answer would be D: Russia signs a treaty with the Central Powers ending its participation in World War I.
