Question

What is a recessive allele?

Answer 1

An allele that can only be expressed when no dominant allele is present

Answer 2

Answer:

B/2. An allele that is only expressed when no dominant allele is present.

Explanation:

Alleles always come in pairs, and we represent them with letters. Uppercase letters represent dominant alleles, and recessive alleles are represent by lowercase letters.

A recessive trait can only appear when the pair of alleles contains 2 lowercase letters, otherwise, if there are 2 uppercase letters or 1 of each, a dominant trait will be seen.

So:

AA - a pair of 2 dominant alleles (here we get a dominant trait).

Aa - a pair of 1 dominant and 1 recessive allele (here we get a dominant trait)

aa - a pair of 2 recessive alleles (here we get a recessive trait).

→ As we can see, we only get a recessive trait when there is a pair of 2 recessive alleles, therefore no dominant alleles in the pair.

Hope it helped,

BiologiaMgaister