The 1962 Constitution, which introduced a presidential system of government in Pakistan, was promulgated by President Ayub Khan. It was officially passed and announced on March 1, 1962, and came into effect on June 8, 1962, though historical records often cite March 18 as the date of formal adoption by the administration.

The 1962 Constitution of Pakistan introduced a presidential form of government. It established a National Assembly at the federal level and Provincial Assemblies for the provinces. Both the central legislature and the provincial legislatures were unicameral in structure, meaning they consisted of a single chamber rather than a bicameral system. This design was intended to streamline the legislative process under the executive-led presidential model of the time.

Under the 1962 Constitution, which established a presidential form of government, the term for the National Assembly was fixed at four years. This was a departure from the parliamentary norms often seen in other democratic systems, reflecting the specific constitutional design implemented during the Ayub Khan era to centralize executive authority.

The 1962 Constitution, which established a presidential system under Ayub Khan, was abrogated on March 25, 1969, when General Yahya Khan took power and imposed martial law. While the option provided is March 23, 1969, historical consensus points to the transition occurring on March 25. This event marked the end of the second constitutional era and the beginning of a new period of military governance.

The 1962 Constitution of Pakistan, like many constitutional documents of the era, included a Preamble. This section served to outline the foundational principles, the ideological basis of the state, and the aspirations of the people, setting the tone for the subsequent articles and provisions within the legal framework of the country.

General Ayub Khan seized power in 1958 and imposed Martial Law. This period of military rule lasted until the promulgation of the 1962 Constitution. The Martial Law was officially lifted on June 8, 1962, which marked the transition from direct military governance to a constitutional framework under the new presidential system. This date is significant in Pakistan's political history as it signaled the end of the first major period of military rule.

The 1962 Constitution of Pakistan, which established a presidential system under Ayub Khan, was abrogated on March 25, 1969, when General Yahya Khan imposed martial law. While some sources might cite dates close to this period due to the transition of power, March 25 is the historically recognized date of the abrogation. The provided option C (March 23) is often associated with Pakistan Day, suggesting a potential factual discrepancy in the source material provided.

The 1962 Constitution introduced the 'Basic Democracies' system, which utilized an indirect election method. The Electoral College was composed of 80,000 Basic Democrats initially, but this number was increased to 85,000 by the time of the 1965 presidential elections. These members were responsible for electing the President and members of the national and provincial assemblies, effectively centralizing power under the executive.

Martial Law, which had been in effect since 1958, was officially lifted on June 8, 1962. This date is historically significant as it marked the transition from direct military rule to the implementation of the new constitutional order, allowing for the formal inauguration of the presidential government.

The 1962 Constitution provided for a federal structure that included a central National Assembly and separate Provincial Assemblies for East and West Pakistan. This dual-level legislative arrangement was intended to balance central authority with regional representation within the framework of the presidential system.