An individual homozygous dominant for the thumb shape mates with an individual homozygous recessive for thumb shape. What are the predicted genotypic and phenotypic ratios for the cross?

A punnet square can be described as a diagram which is made to check the outcomes of a cross.

To check the probability of the offsprings of a cross between homozygous dominant thumb shape parent with a homozygous recessive thumb shape parent, let's draw a punnet square:  

        t              t

T    Tt            Tt

T    Tt            Tt

The results of the punnet square depict that:

Genotype: All of the offsprings will be heterozygous for the thumb shape trait. Tt will be the genotype.

Phenotype: All of the offsprings will show the thumb shape like the thumb shape of the dominant parent.

rtgh gf tfg sxzt hgstr hsd gh trh fhrd rd

substitution is the answer in this case