Question

In the second generation, the dwarf trait
reappears during Mendel's experiment in
monohybrid cross. Why so?​

Answer 1

Answer:

So when male gamete containing recessive allele fuse with the recessive allele of female gamete for same trait in the second generation, the allele combination will become fully recessive and make the phenotype dwarf for the plant height character.

Answer 2

while letting the gene for tallness be T and the gene for shortness be t, the parent genotype of the pea plants in Mendel's experiment are Tt and Tt(this is the monohybrid cross).Using genetic crossing or punnet square, the offspring genotype becomes

            TT     Tt     Tt    and tt

therefore, since it is evident that the gene for tallness is more powerful than the gene for shortness, the first three in the above order will be tall but the last short.Hence the dwarf trait phenotypically expresses itself.