How many possible genotypes and phenotypes are there for a single gene trait that shows dominance in any given population? a. one genotype, one phenotype
b. two genotypes, two phenotypes c. three genotypes, two phenotypes d. two genotypes, three phenotypes

Let D be the dominant allele and d be the recessive allele. Possibilities:
DD (dominant phenotype)
Dd (dominant phenotype)
dd (recessive phenotype)

Therefore, there are three genotypes, two phenotypes.

The answer is C.

The answer is C.Three genotypes, two phenotypes.

Imagine gene for flower colors. Let A allele be dominant and a allele be recessive allele for the trait. A allele is responsible for red color and a allele for white color

The genotypes are:
1. AA
2. Aa
3. aa

However, there will be only two phenotypes:
1. red flowers
2. white flowers

This is because of the dominance of A allele over a allele. So, red flowers will have plants with genotypes AA and Aa while white flowers will have plants with genotype aa.