Answer:
False. An organism with a dominant allele for a particular form of a trait always exhibits that trait.
Explanation:
According to Mendelian genetics, a dominant allele for a given characteristic will always be expressed in the phenotype, regardless of whether its allelic formula is with both dominant alleles or heterozygous.
In the heterozygous form, the dominant allele is able to avoid the expression of the recessive allele, expressing the phenotype. The recessive allele will only be visible in the genotype when both alleles in the pair are recessive.
In non-Mendelian inheritance, however, there are cases where the dominant allele is expressed in conjunction with another allele, such as co-dominance. In intermediate inheritance different alleles —dominant and recessive— are combined and expressed as a combined characteristic.
