Question

In the F2 generation of Mendel’s crosses,
all plants had the dominant trait.
half of the plants had the dominant allele.
all plants had both the dominant and recessive alleles.
one in four plants had two alleles for the recessive trait.

Answer 1

The answer to your question is C

Answer 2

Answer: The correct answer is one in four plants had two alleles for the recessive trait.  

Mendel performed monohybrid cross with respect to the trait, plant height. T represents allele for the dominant phenotype which is tall plant, whereas t represents allele for recessive phenotype which is dwarf height of pea plant.

Parental generation   TT × tt

                                        ↓

F1 generation:       Tt   Tt   Tt  Tt

Parents for the

F2 generation         Tt  × Tt

                                      ↓

F2 generation :       TT  Tt  Tt  tt

Phenotype ( 3:1)       Tall: dwarf

Genotype ( 1:2:1)  

Result: One in the four plants had two alleles for the recessive trait (tt).