Final answer:
The pea plant with the genotype Tt has a tall phenotype because the T allele for tallness is dominant over the t allele for dwarfness. The Tt genotype results in a tall pea plant, not a dwarf one.
Step-by-step explanation:
The correct statement regarding the pea plant with genotype Tt is: Its genotype is Tt, and its phenotype is tall. In genetics, capital letters represent dominant alleles and lowercase letters represent recessive alleles. Since T is the dominant allele for tallness, a pea plant with a Tt genotype will display the dominant tall phenotype, irrespective of the recessive t allele. The dwarf phenotype would only be expressed if the genotype were tt, which indicates the presence of two recessive alleles.