Which of the following statements explains why plants with the genotype Tt and TT would both have a phenotype of tall?

A. The first letter in the genotype indicates the allele received from the male sex cell. The allele received from the male sex is the allele that is expressed.
Incorrect. Allele expression is not determined by which sex cell an offspring receives the allele from.

B. Tallness is the recessive trait for plant height; therefore, the genotypes with Tt and TT would have the same phenotype.
Incorrect. Tallness is a recessive trait in pea plants.

C. Tallness is the dominant trait for plant height; therefore, the genotypes with Tt and TT would have the same phenotype.
Correct!

D. Plants with the genotypes Tt and TT would not have the same phenotypes.
Incorrect. Plants with the genotypes Tt and TT would have the same phenotype.

A pea plant has a yellow pod color. What is the genotype?

A. Gg
Incorrect. A plant with the genotype Gg would have green colored pods.

B. Yy
Incorrect. According to the chart above, green is the dominant color for pod color. The genotype Yy indicates yellow seeds not pods.

C. gg
Correct!

D. Yg
Incorrect. The same letter should be used to show the alleles for a trait.

In guinea pigs, black hair color is dominant to white hair color. Parent one is BB and parent two is bb. What are the correct genotypes of the parents?

A. Parent 1: homozygous recessive;
Parent 2: homozygous dominant
Incorrect. These are not the correct genotypes of the parents.

B.Parent 1: heterozygous dominant;
Parent 2: heterozygous recessive
Incorrect. These are not the correct genotypes of the parents. There are no such genotypes as heterozygous dominant and heterozygous recessive.

C. Parent 1: homozygous dominant;
Parent 2: homozygous recessive
Correct!

D. Parent 1: heterozygous recessive;
Parent 2: heterozygous dominant
Incorrect. These are not the correct genotypes of the parents.

When gametes are formed, gene pairs separate into different sex cells according to the law of —

A. independent assortment
Incorrect. The law of independent assortment states that each gene pair for a trait is inherited independent of the gene pairs for all the other traits.

B. incomplete dominance
Incorrect. The law incomplete dominance does not describe how gene pairs separate during gamete formation.

C. hybridization
Incorrect. Hybridization does not describe how gene pairs separate during gamete formation.

D. segregation
Correct!