We have only one trait with two variations or alleles in this example, which the exercise represents as R or r.
As we can see in the Punnet square, the parent's genotypes are RR x rr, so the offspring would be a probability of 100 % Rr genotype.
Another thing we could appreciate here is that the phenotypes of the parents are different since R (in RR) gives a particular form in the characteristics of the organism, and r (in rr), another one different, but in the offspring, all will be the same observable characteristic gave by Rr genotype.
