The offspring that can be described by the genotype is Gg while for the phenotype is green pod color
The cross between GG and gg give a heterozygous offspring that Gg offspring. The offspring are have a green pod color since the green pod color is dominant over yellow pod color and therefore the offspring have a green pod color. The cross is as the punnet square below.
The lactic acid that is building up in his muscles will eventually cause him to stop exercising. The burning sensation comes from the build up of that lactic acid in his muscles.