Why was the system of checks and balances included in the constitution?

to prevent one branch of the government from becoming too powerful
to keep the president of the united states from vetoing legislation
to slow down the process of government so it doesn't move too fast

Plz which of the following statements about life in europe during the middle ages is not accurate. a. by the middle ages the only unifying factor in europe was christianity. b. most people lived in rural areas and worked on farms. c. priest, monks and church officials were virtually the only people in europe who could read and write d. most people lived in cities or towns and worked as skilled artis most people lived in cities or towns and worked as skilled artisans.