Before revision: The four gases which mainly contribute for cryogenic application and research are O2-B.P.90K , N2-B.P.77K , Helium-B.P.4.2k & H2-B.P.20K .
After revision: The four gases which mainly contribute for cryogenic application and research are O2-B.P.90K ), ( N2-B.P.77K ) ,(()() Helium-B.P.4.2k & H2-B.P.20K .