The Prime Minister and all the Ministers have to be members of Parliament.

Explanation:
The Prime Minister and all the Ministers in a parliamentary system of government are required to be members of the Parliament. This is a fundamental requirement for the functioning of a democratic government.

Parliament:
- Parliament is the supreme legislative body of a country, responsible for making laws and representing the interests of the citizens.
- It is composed of elected representatives who are chosen by the people through a democratic voting process.
- The Parliament is a forum for discussion, debate, and decision-making on important national issues.

Role of the Prime Minister:
- The Prime Minister is the head of government and holds the highest executive position in a parliamentary system.
- The Prime Minister is responsible for leading the government, making important policy decisions, and representing the country at the national and international levels.
- They are accountable to the Parliament for their actions and decisions.

Role of Ministers:
- Ministers are appointed by the Prime Minister to assist in the governance and administration of the country.
- Each Minister is responsible for a specific portfolio or ministry, such as finance, defense, health, education, etc.
- Ministers are expected to formulate policies, implement programs, and address issues related to their respective ministries.
- They are also accountable to the Parliament and have to answer questions, participate in debates, and provide updates on their ministry's activities.

Importance of Parliament Membership:
- The requirement for the Prime Minister and all the Ministers to be members of Parliament ensures that they have a direct connection with the people and are accountable to them.
- Being members of Parliament allows the Prime Minister and Ministers to participate in the legislative process, contribute to policy discussions, and represent the interests of their constituents.
- It also enables them to have a deeper understanding of the issues faced by the citizens and make informed decisions.
- Additionally, parliamentary membership provides a system of checks and balances, as the Prime Minister and Ministers can be questioned, criticized, and held accountable by other members of Parliament.

In conclusion, the Prime Minister and all the Ministers being members of Parliament is a crucial requirement for a functioning democracy. It ensures that the government remains connected to the people, accountable for its actions, and actively involved in the legislative process.