<span>Additional facts:
A test cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring.
Answer:
You'd use it when you wish to see if the one that you think is a homozygous dominant is a purebred, because if you did get a recessive offspring then it proves that the animal is a heterozygous and not a purebred.</span>
Sigmund Freud: The unconscious mind governs behavior to a greater degree than people suspect.
Rosalind Cartwright: Dreams simply reflect life events that are important to the dreamer.
Hope this helped!
-TTL