How can we say that the Prime Minister occupies a unique position in the Parliament?

The Prime Minister occupies a unique position in the Parliament as-

1. It is on the advice of the Prime Minister that the President "summons and prorogues Parliament and dissolves the Lok Sabha."
2. The Prime Minister is the "principal spokesman" and defender of the Government in Parliament. It is he who makes all important announcements of national policies on the floor of the House.
3. Sometimes Ministers' work comes under severe attack in the House. It is the Prime Minister who saves his Ministers from an ugly or unpleasant situation in the House.
4. There are issues like caste wars, corruption by people in positions of authority, price-rise and terrorist attack in the Kashmir Valley which agitated the MPs. If MPs are angry or upset about something, the matter generally ends with the intervention of the Prime Minister.