Pls clarify about nifty 50stocks!!!

[guruvenkatesh2007]

hi market experts,

pls clarify my doubts in nifty 50 stocks!!

1. how nse selecting the scrips for nifty, (its based on volume or company capital.... ??)

2. nifty scrips can up or down how many percentage per day.. its any restrictions??

3. nifty scrips can happen upper freeze or lower freeze on a single day?? its allow in nifty scrips stocks ???

and pls tell interesting information about nifty 50 stocks... it will useful for all

thanks
take care