The main reason is that the USA is in the Northern Hemisphere & Australia is in the Southern Hemisphere. It has all to do with the tilt of the earth as it revolves around the Sun. Summer happens in the hemisphere tilted towards the Sun, and winter happens in the hemisphere tilted away from the Sun.
Iraq it has boundarys that are arbitrarily drawn, with no real common bondage among the people.
B. Topic is under plate tectonics and involves divergence,convergence and transform plate boundary:)
They came because of Rinderpest. Before coming to South America, Africans in Africa depended on cattle such as cows to thrive. But Rinderpest brought to Africa by foriegners began to spread, and the cattle started to suffered from fevers, inflammation in the brain and dysentery. They also had major problems with Europeans and their industries. So they decided to settle in South America.
Hope this helps :)
