Question

why is the progeny always dominant when a ​dominant gene is crossed with a recessive gene?

Answer 1

It should be dominant and recessive allele and not dominant and recessive gene. Wild type allele of a character is fully functional allele that forms an RNA, protein or enzyme for expressing its effect. It is known as dominant allele. Sometimes mutation, insertion or substitution occurs in allele. The modified or mutated allele is known as recessive allele. It is usually nonfunctional. Hence, when a dominant allele is crossed with recessive allele, always in progeny dominant characters appear.