When a bicycle coasts uphill it moves slower and slower as it climbs why?

Because gravity is trying to pull it down but at the same time you on the bike are trying to pull it up?

The correct answer is b, social stratification is needed for a society to exist. marxist theory regarding social stratification is that due to the differing economic capacities among people in society, a natural separation occurs between those that own the means of production and those that sell their labour in the production chain. 

For the sat there is a reading test, math test, and a writing and language test. the act has social studies and science tests.