Which of the following statements is true? a. the genotype is the physical appearance of a trait. b. alleles, genes, and loci are different names for the same thing. c. the phenotype of a dominant allele is never seen in the f1 progeny of a monohybrid cross. d. a testcross can be used to determine whether an individual is homozygous or heterozygous for a dominant allele.

d. a testcross can be used to determine whether an individual is homozygous or heterozygous.

Explanation:

In genetics, testcross, designed by Gregor Mendel, is designed to determine whether an individual exhibiting a dominant biological character is homozygous or heterozygous for that character. Simply put, a testcross determines the genotype of an individual with a dominant phenotype. Therefore, we can conclude that the right answer to your question is the letter D.

the answer is a