In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A freckled tongue-roller could have which of the following genotypes?
A)RRFF
B)RrFf
C)rrFF
D)RRFF and RrFf only
E)All of these choices are correct.

Question

Quizplus · Accepted Answer

A freckled tongue-roller could have the genotypes RRFF or RrFf because both combinations include at least one dominant allele for tongue rolling (R) and at least one dominant allele for having freckles (F), which are necessary to express these traits.

In Humans, Ability to Roll the Tongue (R) Is Dominant