How to display the mass fraction of gas components?

Why are the options for these gas components grayed out and unchecked after the chemical reaction is added?What do I have to do to output the gas mass fraction?
Here’s my arithmetic file, looking forward to any possible answers, thanks!

combustionCase(1).mfx (21.3 KB)

This is because you have turned off species equations for the gas phase. Go to the Fluid pane and turn the species equations on.