What is the difference between parliamentary and presidential government

Democratic regimes are divided into parliamentarians or presidentialists. The first were born in the monarchies, winning for Parliament, step by step, greater powers, until arriving -as in England- to which the Queen can reign but not govern. The presidentialisms, for their part, were born with the modern republics, reluctant to monarchs and aristocrats, the first of which was the United States, in 1776, in which the colonies formed a confederation, each retaining its particular sovereignty.

The great difference is that in parliamentarism the executive branch is composed of a president or a monarch, head of state, with limited powers, and a government appointed by Parliament, which at any time can censor. In presidentialism, however, the head of state and government coincide in the same person, are not subject to parliamentary censure and the Legislative Branch is limited to the area of law making.

they were the direct result of some cultural difussion.

they united the colonies in their fight against the british.