How did members of the upper class support one another to remain in the upper class? What is this called?

In other words, one's membership in a particular social class is based on ... who do low level service work,

the answer is: c. c.it limited the president’s power to start wars.

the war powers resolution of 1973 requires the president to notify the congress whenever the president wanted to order a military operation to other countries within 48 hours. if after being reviewed the congress disagree with the proposal, that the president will be banned from ordering the operation.