The organ that looks after the day to day work of UN is___________
(A) Economic and Social council
(B) General Assembly
(C) Security Council
(D) Secretariat

Hint: The United Nations is a global association established in 1945after the second World War. It is at present composed of 193 Member States. The mission and work of the United Nations are guided by the reasons and standards contained in its establishing Charter. Every one of the 193 Member States of the United Nations is a part of the General Assembly. States are admitted to participation in the UN by a choice of the General Assembly upon the suggestion of the Security Council.

Complete answer:
The Secretariat includes the Secretary-General and a huge number of worldwide UN staff individuals who complete the everyday work of the UN as commanded by the General Assembly and the Organization's other head organs. The Secretary-General is the head of the Organization. He is delegated by the General Assembly on the proposal of the Security Council for a five-year, inexhaustible term. UN staff individuals are selected globally and locally, and work in obligation stations and on peacekeeping missions all around the globe. However, serving the reason for harmony in a savage world is a hazardous occupation. Since the establishment of the United Nations, several valiant people have given their lives in its administration.

Thus, option (D) is correct.

Note: The United Nations (UN) was the second multipurpose global association set up in the twentieth century that was worldwide in extension and participation. Its archetype, the League of Nations, was made by the Treaty of Versailles in 1919 and disbanded in 1946. Settled in New York City, the UN likewise has provincial workplaces in Geneva, Vienna, and Nairobi. The dialects used for its conduct of office are Arabic, Chinese, English, French, Russian, and Spanish.