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. A teacher reports that after testing her class on the ability to roll their tongue, with very little
effort the non-tongue-rollers can learn to also roll their tongues.
B. A student who can roll his tongue has a mother and father, both of whom cannot.
C. A student who cannot roll his tongue has a mother and father, both of whom can.
D. Both A and B are situations that would cast doubt on this assumption.

D. Both A and B are situations that would cast doubt on this assumption

they are:

A. A teacher reports that after testing her class on the ability to roll their tongue, with very little effort the non-tongue-rollers can learn to also roll their tongues.

B. A student who can roll his tongue has a mother and father, both of whom cannot.

Explanation:

A traits is a special characteristics  or qualities that is common to an organism. it is usually passed down/ inherited from parents to offspring or as a result of environmental factors. some traits that are inherited from parents cannot be inherited from the environment those are genetically inherited characteristics.

Tongue rolling is a simple genetic traits that is capacity of an individual to roll the lateral edges of the tongue upwards into a tube. it is inherited from one parent.

The  option A and B contradicts  as it is not a learn characteristics but an inherited trait. and student can only role his/her tongue if one of the parent has that special ability to role the tongue and if that trait was passed to that child. so a student cannot possess that ability to roll the tongue if their parents do not have it.

the correct answer is the following is a list of inventions made in the medieval islamic world, especially during the "islamic golden age" (8th to 13th centuries),[1][2] as well as the late medieval period, especially in the emirate of granada and the ottoman empire.

science and technology in the islamic world adopted and preserved knowledge and technologies from contemporary and earlier civilizations, including persia, india, china, and greece-roman antiquity, while making a number of improvements and innovations.

answer; repetitive thoughts; ritualistic behaviors;