If an organism that is homozygous dominant is crossed with a heterozygote for that trait, the offspring will be __________.

• A. three-quarters of the dominant phenotype and one-quarter of the recessive phenotype
• B. all homozygous dominant
• C. all homozygous recessive
• D. present in a 9:3:3:1 ratio
• E. all of the dominant phenotype

Answer: (E)

Verified step by step guidance

1. Identify the genotypes of the parents. A homozygous dominant organism has two dominant alleles (e.g., AA), while a heterozygote has one dominant and one recessive allele (e.g., Aa).
2. Set up a Punnett square to predict the genotypes of the offspring. Place one parent's alleles on the top and the other parent's alleles on the side.
3. Fill in the Punnett square by combining the alleles from each parent. This will show all possible genotypes of the offspring.
4. Analyze the genotypes from the Punnett square. The possible genotypes are AA and Aa, both of which express the dominant phenotype.
5. Conclude that all offspring will display the dominant phenotype, as both AA and Aa result in the expression of the dominant trait.