Timothy has attached earlobes like his maternal grandfather. his mother and father both have free earlobes, which are dominant. which statement best explains how timothy inherited attached earlobes?
a).he received a dominant allele from each parent
b).he received a dominant allele from his father and a recessive allele from his mother
c). he received a dominant allele from his mother and a recessive allele from his father
d). he received a recessive allele from each parent

Option D, He received a recessive allele from each parent

Explanation:

The dominant allele in this case is free earlobes which is represented by "F"

The recessive allele is attached earlobe which is represented by "f"

Now, it is known to us that a recessive trait will be expressed only when both the alleles in the offspring are recessive.

Thus, Timothy must have "ff" genotype.

Since both of his parents are having dominant free earlobes, thus they both must be carrier of the recessive traits "f" in order to produce "ff" genotype

Thus the genotype of parents is

Ff and Ff

When a cross is carried out the following offsprings are produced

FF, Ff, Ff, ff

Hence , it can be said that Timothy received a recessive allele from each parent

Therefore, option D is correct

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