PATHOLOGY

Detailed explanation-1: -A dominant trait will always be expressed in the offspring if the dominant allele is present, even if there is only one copy of it (heterozygous or dominant homozygous, Aa or AA).

Detailed explanation-2: -ANSWER: Dominant is always expressed when present. Recessive is only expressed when no dominant genes are present. Compare dominant and recessive genes and traits and observe them in humans.

Detailed explanation-3: -Dominant alleles show their effect even if the individual only has one copy of the allele (also known as being heterozygous?). For example, the allele for brown eyes is dominant, therefore you only need one copy of the ‘brown eye’ allele to have brown eyes (although, with two copies you will still have brown eyes).

Detailed explanation-4: -Whether an allele is dominant or not does not affect how common a trait is. Now of course traits can become more common over time. The changes just don’t have anything to do with whether the trait is dominant or not.