Which cross involves two traits?

A dihybrid cross specifically involves the study of two distinct traits simultaneously. This form of genetic cross examines how these two traits segregate and assort independently during gamete formation and inheritance. The classic example of a dihybrid cross is examining the inheritance of two traits in pea plants, such as seed shape (round vs. wrinkled) and seed color (yellow vs. green).

In this scenario, each parent contributes alleles for both traits, resulting in a diverse set of combinations in their offspring. The principles derived from dihybrid crosses helped establish Mendel's law of independent assortment, which states that alleles for different traits are distributed to gametes independently of one another.

Monohybrid crosses, on the other hand, study only one trait, while a test cross is utilized to determine the genotype of an individual with a dominant phenotype by crossing it with a homozygous recessive individual. Independent assortment refers to the genetic principle that describes how different genes independently separate from one another when reproductive cells develop, but does not refer to a specific type of genetic cross. Thus, the emphasis on two traits makes the dihybrid cross the correct response in this context.