单选题　　The United States Congress is a bicameral legislature. Two Houses-Senate and House of Representatives make the laws. Before a bill may be sent to the President to sign, both houses must approve. When great agreement exists on a bill, the law moves quickly. However, most suggested laws are complex and relate to interests and conflicts which need debate and careful consideration. 　　Both houses of Congress use the committee system to handle the numerous bills. A bill is referred to the committee responsible for that category ― whether taxation, foreign affairs, housing or whatever. In the committee the bill is studied, arguments are collected for and against, and advice is gathered from experts on the subject. Citizens have the chance to influence legislation through the committee system. If the committee votes favorably, the bill goes before the entire house. Usually committee approval means favorable action by the Senate and House of Representatives. 　　As a result, membership on the more important committees is eagerly sought. How long a senator or representative has served in Congress is most important in assigning committee memberships Usually the majority political party receives a majority of the memberships of each committee. In this way the party controls decisions because the real work and power of Congress lies in the system of committees. Some people protest that this system restricts laws, but most see this as the system that works best.