Feudalism helped protect communities from the violence and warfare that broke out after the fall of Rome and the collapse of strong central government in Western Europe. Feudalism secured Western Europe's society and kept out powerful invaders. Feudalism helped restore trade. Lords repaired bridges and roads.
The correct answer is: "He developed mathematical principles"
René Descartes (1596 – 1650) was a French philosopher, mathematician, and scientist who lived more than 20 years in the Dutch Republic and was one of the main figures of the Dutch Golden Age.
His great influence in mathematics has been his major contribution to the Scientific Revolution, although his work in philosophy is outstanding too. He developed the the Cartesian system of coordinates. He is considered the father of analytical geometry, which connects both algebra and geometry and which has been used in the development of infinitesimal analysis and calculus .
To maintain separation of powers, and to maintain the popular vote are both correct!
B: The study of government policy and the economy.
