In humans, the gene for a free earlobe (E) is dominant over the gene for an attached earlobe (e). If one parent has a free earlobe (Ee) and the other parent has an attached earlobe (ee), what is the probability that their offspring will have an attached earlobe? A- 0%
B- 25%
C- 50%
D- 100%

C- 50%

Explanation:

If you draw a Punnett square, you can see the chances of the offspring's genotype (the various E/e combinations)

     E   x    e   (parent 1)

e     E e     e e

e     E e     e e

^( parent 2)

There is a 50% chance of having E e and 50% chance of having e e. Since attached earlobes are recessive, there is then a 50% chance that the offspring will have e e.