The Ability to Roll Your Tongue into a U-Shape Is

Short Answer

The ability to roll your tongue into a U-shape is a recessively inherited trait.What are all the possible parental combinations that would produce a child heterozygous for this trait? List the parental combinations as [Parent 1 genotype] × [Parent 2 genotype].Use the letters "R" and "r" to designate dominant and recessive alleles,respectively.As an example,note that "RR × rr" is equivalent to "rr ×RR"; thus,you only need to list one,not both.