What type of cross examines two traits at once?

A dihybrid cross is used to examine the inheritance of two traits simultaneously. This approach allows researchers to observe how different combinations of alleles for each trait segregate during gamete formation and eventually phenotypically express in the offspring. This type of cross is particularly useful in genetic studies to determine the principles of independent assortment, as it showcases how two different traits can be inherited independently of one another based on Mendelian genetics.

In contrast, a monohybrid cross focuses solely on one trait, analyzing how two alleles for that single trait interact. A back cross involves breeding a hybrid organism with one of its parents or an organism genetically similar to its parent, primarily utilized for determining the traits of offspring rather than examining multiple traits at once. A purebred cross refers to breeding within the same genotype to preserve certain traits inherited in a homozygous state, which also does not involve the examination of two traits together. Therefore, the dihybrid cross stands out as the correct answer for studying two traits concurrently.