Why did vassals have to serve lords? Pls help

D.q. were political reforms in the progressive era a good example of american democracy?

The largest city in brazil, sao paulo, has a population of about 11 million. based on the rank-size rule, what is the population of the second-largest city, rio de janeiro, most likely to be? a. 8 – 10 million b. 5 – 6 million c. about 3 million d. about 1 million

Why was the bill of rights so important to new york and virginia