The correct answer is: Cross the green-pod plant with a yellow-pod plant.
Yellow-pod plant phenotype is known to be homozygous recessive. In this case, we would use test cross to determine whether there are any recessive alleles in the unknown. Â The recessive homozygote (yellow-pod plant) will contribute an allele for the recessive characteristic to each offspring, the second allele (from the unknown genotype, green-pod plant) will determine the offspring's phenotype.
