Dominant alleles are ones that are common in a population of organisms.
a. true
b. false

b. False

Explanation:

We call the dominant allele one who alone can express a particular trait. The recessive allele can only express itself in pairs.

We didactically represent the genes by letters, with the capital letter used to represent dominant alleles and lowercase letters used for recessive alleles. By convention, we always use the recessive characteristic letter and the uppercase letter before the lowercase. When an individual has both equal alleles, we say that he is homozygous (eg, BB and bb); whereas when he has different alleles (eg, Bb), we say he is heterozygous.

To better illustrate what recessiveness and dominance are, let's take for example albinism, a condition that makes melanin production impossible. We will represent the dominant allele for A and the recessive allele for a. This feature is determined by a pair of recessive alleles, ie a person is considered albino only if he has a recessive allele inherited from his mother and another from his father. We call albinism recessive inheritance.

Since albinism only occurs when the individual is aa, an AA or Aa person has a normal phenotype. This demonstrates that the presence of only one dominant allele is already responsible for melanin production. Note that an AA person does not have darker skin than an Aa person, we can only conclude that they are capable of producing pigmentation.

Among the dominant inheritance, we can mention the ability to curl the tongue and polydactyly (presence of more than five fingers or toes).