Being able to roll the tongue is dominant over not being able to roll the tongue.

R R

r Rr Rr

r Rr Rr

What is the probability that the offspring will be unable to roll the tongue?

0

2

3

4

For a cross in which the genotypes of the parents are homozygous dominant RR, the offspring by 0% will be unable to roll the tongue. Probability: 0

For a cross in which the genotypes of the parents are heterozygous, Rr, 25% of offspring will be unable to roll the tongue.

For a cross in which the genotypes of the parents are homozygous recesive rr, the offspring by 100% will be unable to roll the tongue. Probability 1

0/4 0% is the possibility That the offspring will not be able to roll the toungue