Recessive alleles are best defined as alleles that are expressed only in a double dose
Step-by-step explanation:
According to Mendelian genetics there are 2 different alleles that cause the expression of certain characters in an individual. Mostly one comes from the maternal parent and the other comes from the paternal parent.
If it is dominant then it can get expressed even if a single copy of the gene is present whereas if it is recessive it required 2 copies to be present to express the disease.