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.
the executive branch is made up of a prime minister and his or her cabinet. They are chosen by the parliament, which is the lawmaking branch. The prime minister and cabinet are themselves members of the parliament. There are fewer conflicts between the executive and legislative branches in a parliamentary government. However, only the presidential form of government has checks and balances.