A test cross A) is used to determine if an organism that is displaying a dominant trait is heterozygous or homozygous for that trait. B) is used to determine if an organism that is displaying a recessive trait is heterozygous or homozygous for that trait. C) causes the loss of hybrid vigor. D) results in an F₂ generation with a phenotypic ratio of ³/₄ dominant to ¹/₄ recessive. E) results in the same alleles being transferred from generation to generation.

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A test cross is used to determine if an organism that is displaying a dominant trait is heterozygous or homozygous for that trait. This is achieved by crossing the organism with a homozygous recessive individual and observing the phenotype of the offspring. If the dominant trait is heterozygous, then approximately half of the offspring will display the recessive trait, while the other half will display the dominant trait. If the dominant trait is homozygous, then all of the offspring will display the dominant trait.

A Test Cross