Answer:
25%
Explanation:
male
can roll tongue - cannot roll tongue
female
can roll tongue - cannot roll tongue
If they have a child, the possible combinations are:
1)
father's gene: can roll tongue
mother's gene: can roll tongue
RESULT = THE CHILD WILL BE ABLE TO ROLL HIS/HER TONGUE
2)
father's gene: can roll tongue
mother's gene: cannot roll tongue
RESULT = THE CHILD WILL BE ABLE TO ROLL HIS/HER TONGUE
3)
father's gene: cannot roll tongue
mother's gene: can roll tongue
RESULT = THE CHILD WILL BE ABLE TO ROLL HIS/HER TONGUE
4)
father's gene: cannot roll tongue
mother's gene: cannot roll tongue
RESULT = THE CHILD WILL NOT BE ABLE TO ROLL HIS/HER TONGUE