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.
There are similarities and differences between a parliamentary democracy and a presidential democracy. One similarity is that in both forms of government, the people elect their representatives. This gives the people significant power since they are able to decide who will represent them. There are differences between the two forms of democracy. The United States has a presidential democracy, while the United Kingdom has a parliamentary democracy. In a presidential democracy, separation of powers is important. There are specific jobs that each branch of government has.