help please with these questions, thank you

Unit 3 DQ: Corporate Form of ownership (Graded) Earned Capital and Contributed Capital are other names for Retained Earnings and Paid-in Capital. When a company issues common stock they credit the par value (if any) and the paid.in capital account Discuss the reason why transactions in the daily stock markets (NYSE, etc) do not affect these two accounts. If a company buys back its own stock how are these accounts affected? Please provide details and examples in your discussion