12 April 1973. This Constitution, called the Constitution of the Islamic Republic of Pakistan 1973, was promulgated on 14 August 1973. On the same day, Mr. Zulfiqar Ali Bhutto took oath as the Prime Minister, while Mr. Fazal Illahi Choudhary took oath as the president of Pakistan. The 1973 Constitution provides for a parliamentary form of government where the executive authority of the state vests with the Prime Minister. The President, according to the Constitution, is at the apex, representing the unity of the Republic. From 1947 to 1973, the country had had a unicameral system, but under the 1973 Constitution, Pakistan adopted a bicameral federal legislature, called Parliament, composed of the President, the Senate and the National Assembly. Originally, the general seats of the National Assembly were 200 with additional 10 seats reserved for women, bringing the total strength to 210. The newly created Upper house i.e. the Senate had 63 members. Later in 1985 through a Presidential Order (P.O. No. 14 of 1985), seven seats were added to the general seats and ten to the reserved seats for women in the National Assembly. Ten seats were exclusively reserved for minorities to be filled through separate electorate system. Thus the total strength of the lower house reached to 237 members. Similarly the size of the Senate was also increased from 63 to 87 members. Under the 1973 Constitution the National Assembly is elected for five years term, unless sooner dissolved. The seats in National Assembly, unlike the Senate, are allocated to each province and other units of the federation, on the basis of population. The Constitutional provision of 20 special seats for women lapsed in 1990, thus decreased the Assembly strength from 237 to 217. Under the Constitution, elections to the 10 seats reserved for minority were held on separate electorate basis. Despite the tenure of the Assembly being five years, as prescribed in the Constitution, Mr. Z.A. Bhutto, on 7 January 1977 announced the holding of elections before time. Consequently, on 10 January 1977, he advised the president to dissolve the National Assembly. Elections were held on 7 March 1977. The opposition charged the government with rigging the elections to the National Assembly and thereafter boycotted the Provincial Assemblies elections. Since the opposition had not accepted the National Assembly elections result, they did not take oath. This resulted in severe political crisis and Martial Law was imposed by