Round (r) seed shape is dominant to wrinkled (r) seed shape in pea plants. if an rr plant is crossed with an rr plant, what is the frequency of phenotypes in the f2 generation? a. all wrinkled seeds b. all round seeds c. 1/4 rr, 1/2 rr, 1/4 rr d. 3 round seeds, 1 wrinkled seed e. none of the above

The correct answer is b. All round seeds

Explanation:

If an RR plant is crossed with an rr plant than all the phenotype will produce round seed and the frequency of the Round seed plant to wrinkled seed plant would be 4:0.

                       R     R

                  r   Rr    Rr

                  r   Rr    Rr

So all the phenotypes will be heterozygous dominant for the round seed which means that all phenotypes will have a single dominant allele for round seed which is enough to express round seeds in the phenotypes.