Explanation:

1. Presidents all over the world are not always nominal executives like the President of India. In  many countries of the world, the President is both the head of the state and the head of the  government.
2. The President of the United States of America is the most well-known example of this kind of  President. The US President is directly elected by the people. He personally chooses and appoints  all Ministers.
3. The law making is still done by the legislature (called the Congress in the US), but the president  can veto any law. Most importantly, the president does not need the support of the majority of  members in the Congress and neither is he answerable to them.
4. He has a fixed tenure of four years and completes it even if his party does not have a majority in  the Congress. This model is followed in most of the countries of Latin America and many of the exSoviet Union countries.
5. Given the centrality of the President, this system of government is called the Presidential form of  government.
6. In countries like ours that follow the British model, the parliament is supreme. Therefore our  system is called the parliamentary system of government.