The term of Australian parliaments is determined by the opening and dissolution (or expiration) of the House of Representatives. The Senate is not normally dissolved at all, except at a double dissolution, when the entire parliament is dissolved. Parliaments may be divided into one or more sessions. Each session except the last must be prorogued before a new session can begin. One of the effects of prorogation is that it prevents the Senate from meeting and conducting its business after the House of Representatives has concluded its business.