As I am preparing an essay paper.

As I am preparing an essay paper. I had some following questions below that I feel will help me built more ideas to write about my paper. I needed some feed back by answering the following questions to help me out.

Why is there a limitation on the amount of money we have to pay tax on for Social Security and not for Medicare?

 Is it fair that those earning more in wages or earning through dividends and capital gains get to pay less towards Social Security as a percentage of income?