Question

in a genetic cross, what does a recessive allele require to be expressed?
a. a heterozygous genotype
b. a homozygous dominant genotype
c. at least one dominant allele
d. two recessive alleles

Explanation:

In genetics, a recessive allele is masked by a dominant allele. It is only expressed when an individual has two copies of the recessive allele (homozygous recessive genotype). A heterozygous genotype has one dominant and one recessive allele, where the dominant allele is expressed. A homozygous dominant genotype has two dominant alleles. And having at least one dominant allele means the dominant trait will be seen.

Answer:

d. Two recessive alleles