The ability to roll the edges of the tongue upward in a U-shape has been considered to be an inherited ability.The standard assumption is that tongue-rolling is a dominant allele at a single gene locus.Which of the following would cast doubt on this assumption?
A)Behaviors are not inherited,only structures are inherited.
B)A student who cannot roll his tongue has a mother and father,both of whom can.
C)A student who can roll his tongue has a mother and father,both of whom cannot.
D)With very little effort the non-tongue-rollers can learn to also roll their tongues.
E)A student who can roll his tongue has a mother and father,both of whom cannot roll their tongues AND with very little effort the non-tongue-rollers can learn to roll their tongues.

Question

Quizplus · Accepted Answer

The assumption that tongue-rolling is a dominant allele at a single gene locus would be cast into doubt if a student who can roll his tongue has a mother and father, both of whom cannot roll their tongues AND with very little effort the non-tongue-rollers can learn to roll their tongues. This would suggest that tongue-rolling is not a purely genetic trait, but rather a learned behavior.

The Ability to Roll the Edges of the Tongue Upward