Answer:
The correct answer is -
The phenotype of offspring (first cross or F1): 100% tall
The genotype of offspring (first cross or F1 - 100% Tt or heterozygous)
The phenotype of offspring in F2 (F1 × F1) - 3:1 (3 tall: 1 dwarf)
The genotype of offspring in F2 (F1 × F1) - 1:2:1 (One dominant tall: two heterozygous tall: one dwarf)
Step-by-step explanation:
In this experiment of Mendel, Mendel selected the pea plant as it has various characters, short life span, and easy to breed. For this, he used two true breed lines, tall plants that had dominant allele TT and dwarf plant tt (recessive). In presence of the dominant allele, recessive alleles do not show their characteristics and only express if both alleles are recessive.
In the first cross of TT and tt
Gametes: T and t
offspring: Tt
the offsprings are all tall and heterozygous which means one dominant and one recessive allele.
second cross or F1 × F1
Tt × Tt
gametes: T, t and T, t
offspring: TT, Tt, Tt, tt
Thus,
The phenotype of offspring (first cross or F1): 100% tall
The genotype of offspring (first cross or F1 - 100% Tt or heterozygous)
The phenotype of offspring in F2 (F1 × F1) - 3:1 (3 tall: 1 dwarf)
The genotype of offspring in F2 (F1 × F1) - 1:2:1 (One dominant tall: two heterozygous tall: one dwarf)