The processes that use the mechanisms are: Cellular respiration â ATP is generated by oxidation of organic molecules, the passage of electrons down an electron transport chain, and chemiosmosis. The final electron acceptor is almost always inorganic. Aerobic â the final electron acceptor is O 2.
The Sumerians lived in Mesopotamia around 4000 BC. Mesopotamia or the Fertile Crescent was a region in the Middle East between the Tigris and Euphrates rivers, in the territory of modern Iraq, Iran and Syria.
The Sumerians also made a very important invention--the wheel. The invention of the wheel made it possible to pull heavy loads. The Sumerians formed several city-states. City-states are nations the size of cities. Walls around each city-state protected the citizens from outside invaders. Farmland was usually outside the city walls, and people would seek protection from the walls of the city when under attack.