The Sumerians were the first people to migrate to Mesopotamia, they created a great civilization. Beginning around 5,500 years ago, the Sumerians built cities along the rivers in Lower Mesopotamia, specialized, cooperated, and made many advances in technology. The wheel, plow, and writing (a system which we call cuneiform) are examples of their achievements.
1 In a presidential system, the legislature and the executive do not have to be aligned and often work against each other. 2  Policy implementation can be much slower and more moderated, at least in the US system.
At the time of crisis the Presidential executive is more successful in taking prompt and bold decisions than the Parliamentary government. 8. The Presidential system of government provides more political stability than the Parliamentary form of government. 9. As the government in the parliamentary system is responsible to the Parliament, it is more democratic and respectful of public opinion than the Presidential executive which is not responsible to the legislature.