Define the below: Social Stratification Social differentiation Social inequality

Define the below:
Social Stratification
Social differentiation
Social inequality
social mobility
corporate class
wealthfare
postindustrial societies
progressive taxation
purchasing power parity (PPP)
income inequality

Answer the below in a least 4 full paragraphs:

1. What are the five general types of human stratification systems from human history? Briefly describe each and provide the system our society structures with. What is the level of social inequality in a society related to? Has inequality improved throughout history or become worse? summarize the ups and downs of social inequality in human history.

2. Define class. who is the corporate class? How and why has the corporate class become more important and powerful than the upper class in recent years? Provide at least three arguments for their position.