Which gas is most likely to be found in the troposphere? [Hint: Consider the location of the ozone layer to answer parts (a) and (b).] O Ne, He, CH4, H, NO, NO2, NH3, and CO are lighter than ozone and will be found above the ozone layer. O Kr, Xe, SO2, and I2 are heavier than ozone and will be found below the ozone layer. QI is the most dense of the trace gases. O 02, N2, CO2