Dear student,
The crossing of tall (TT) and dwarf (tt) plant by mendel led to the formation of heterozygous tall (Tt) F1 offspring.
Reason for the observation of F1 offspring
Since the genotype of F1 offspring is Tt and T is dominating allele therefore the phenotype of offspring will be tall.
The self fertilization of F1 heterozygous (Tt) gives gives F2 offspring whose phenotypic ratio is 3:1 and genotypic ratio is 1:2:1. Three types of offspring will be generated TT, Tt, tt
Reason for the observation of F2 offspring
Phenotypic ratio is 3:1 and genotypic ratio is 1:2:1 where one offspring is TT, and two Tt and one offspring is tt. The dominant allele is T in all the three offspring therefore they are tall but one offspring is tt which is recessive gene so it is dwarf.
Regards