How many copies of a dominant allele of a specific trait does a child need to exhibit that trait?

The correct answer will be- only one copy of the dominant allele of a specific trait is enough to exhibit that trait.

Explanation:

Mendel's Law of Dominance states that dominant allele will always mask the recessive allele. Therefore, a cross between a homozygous recessive and a homozygous dominant allele will always express the dominant trait, while still having a heterozygous allele in genotype.

So, according to the law of dominance, the child with only one copy of the dominant allele will have that specific trait because the dominant allele will mask the recessive allele.

Thus, the correct answer would be one copy.