A Testcross Is Used to ____

A testcross is used to ____.

A) determine if a parent with a dominant trait is heterozygous or homozygous
B) determine which allele is dominant
C) determine if the progeny of an experimental cross will have a random assortment of alleles
D) prove an organism is double recessive
E) cross an individual with a dominant phenotype with a homozygous dominant individual to prove the alleles are dominant