If T stands for tall pea plant and t stands for short pea plant, what is the phenotype of a pea plant with allele combinations Tt, TT and tt. You should have an answer for each combination.

Tt will be tall phenotypically, TT will be tall phenotypically, tt will be short phenotypically.

Explanation: From the information provided above, T stands for tall pea plant. This indicates that T is dominant because dominant alleles are written in upper cases. t stands for short pea plant. This indicates that t is recessive because recessive alleles are usually written in lower cases.

A dominant allele has the ability to express itself in the presence of a recessive allele, it masks the effect of a recessive allele. A dominant allele will express itself both in a homozygous and heterozygous state. A recessive allele do not have the ability to express itself in the presence of a dominant allele, its effect is masked by a dominant allele. A recessive allele can only express itself in a homozygous state.

Therefore, T will express itself as tall pea plant both in Tt and TT while t will express itself as short pea plant in tt.