B. helped prevent and cure diseases like tuberculosis and polio.
Feudalism is a practice that has been used around the globe at different times, but was made famous for its use in Europe during the Middle Ages. Feudalism set up a system of control whereby nobles had control over fiefdoms or territories that were run by vassals, whereby they provided some degree of safety or protection for the vassals in return for payment through crops or some form of money.
They need the warrant so that the citizen is sure that they are police, and because without one, it would technically be trespassing.
