AP BIOLOGY

Detailed explanation-1: -If the results of a test cross reveal that all the offspring resemble the parent being tested. This parent must be homozygous because all the gametes of parents carry the same allele that fuses to form same offsprings.

Detailed explanation-2: -Two-Gene Test Crosses Test crosses operate under the same principle no matter whether you are considering one gene or multiple genes; in all cases, you are crossing an individual of a dominant phenotype but unknown genotype to an individual that is homozygous recessive for all relevant genes.

Detailed explanation-3: -Outcomes Of The Test Cross If the outcome of the test cross is a recessive progeny, then it is deduced that the parent is heterozygous for the allele being tested. If the outcome of the test cross is a dominant progeny phenotypically, then the parent is a homozygous dominant for the allele being tested.

Detailed explanation-4: -If the test cross results in any recessive offspring, then the parent organism is heterozygous for the allele in question. If the test cross results in only phenotypically dominant offspring, then the parent organism is homozygous dominant for the allele in question.