Stock market is the market in which the companies raises capital thorugh issuong shares to the public
Primary market is the market in which the companies sell therir shares to rhe lublic
But in secondary market the company
Sell their shares and the public will buy the shares and as well as the buyers and sellers buy and sell their shares inorder to maximise their returns
SENSEX is the average of performance of top 30 companoes in BSE
NIFTY is rhe average of performance of top 50 companoes in NSE