The 150 members of the house are elected from single-member geographic districts (popularly known as "seats" but officially known as "Commonwealth Electoral Divisions") which are intended to represent reasonably contiguous regions, with relatively equal population in each of about 80 000 people. Voting is by the preferential system.
According to Australia's Constitution, the powers of both houses are nearly equal with the consent of both houses needed to pass legislation. In practice, however, the "House" or "Lower House" as it is called, is far stronger in some ways, and far weaker in others.
By convention, the party or coalition in the lower house with a majority is invited by the Governor-General to form government, and thus the leader of the party in the lower house becomes the Prime Minister of Australia and his senior colleagues ministers responsible for various government departments. Bills appropriating money can also only be introduced or modified in the lower house. Thus, only parties in the lower house can govern. However, in the rigid Australian party system, this ensures that virtually all contentious votes are along party lines, and the government always has a majority in those votes. The Opposition's only real role in the House is to present arguments why the government's policies and legislation are wrong, and attempt to embarrass the government as much as possible by asking difficult questions at question time. The Senate, by contrast, has not had any single party or coalition holding a majority in many years, so votes in the senate are actually meaningful. The House's parliamentary committee system is also embryonic as compared to the well-established Senate committee system.
In a reflection of the color scheme of the House of Commons, the House of Representatives is decorated in green.