sentences:  Rajya Sabha is a permanent house, and is not subject to dissolution, and the members serve staggered terms- one-third of the membership retires every two years.Vacancies in both houses, whether because of death or resignation of a member, are filled with by-elections within six months of the vacancy - the newly elected member in which case serves only the rest of the pending term of the seat they are elected to.The number of seats in both houses is regulated by Constitution and parliamentary statutes.