Suppose and alien life form is discovered on another planet that takes in ch4 from the atmostphere. which of the following could be used to determine what happens to the ch4 after the organism consumes it? a) chromatography b) radioactive tracers c) x-ray diffraction d) organic synthesis

I am guessing radioactive tracers?  
because x-ray diffraction wouldn't let you view tiny molecules.
organic synthesis is when you create molecules which doens't make sense.
Chromatography maybe, but you would have to take a small sample and put it in a machine.  
Tracers would let you look for the carbon molecules later.