The correct answer to this open question is the following.
In simple terms, the parliamentary and presidential democracies different in that citizens elect the chief executive in presidential democracies. On the other hand, legislators elect the chief executive in parliamentary democracies.
Although both are democracies, both systems have notorious differences in the way they elect government officials. In a presidential democracy, it is the citizens who directly vote to select the President and their representatives. That is the case of the United States and México.
In the case of parliamentary systems, people vote for their representatives, and once they are elected in Parliament, these members of the Parliament elect the Prime Minister.
In the case of Canada, it consists of a Crown and a Government General. The sovereign government is vested in the crown of England, and the exercise of government or the direct operation and management of the government relies on the Governor-General, which is represented by the Canadian Prime Minister and the Canadian Parliament.