Here is a specimen paragraph. Compare it with yours. 

The northern and southern polar regions are different in many ways. The most important difference is in terms of the distribution of land and water. The northern Arctic region is an ice-covered sea, almost completely surrounded by land. The Antarctica, on the other hand, is a huge continent which is surrounded by a great ocean: Because of this, other differences occur. The Arctic has a varied climate, while the Antarctic climate varies little. It rains more in the Arctic than in the Antarctic. Although the Arctic has plant life, the Antarctica is an empty desert. Whereas the Arctic has been exploited economically for centuries, trade has never really touched Antarctica. 

(Adapted from K. Johnson: Communicate in writing)