What is the phenotypic ratio of a monohybrid cross between two heterozygous parents?
select one:
a. 1: 2: 1
b. 9: 3: 3: 1
c. 1: 2: 2: 1
d. 3: 1

The Phenotypic ratio in a monohybrid cross between two heterozygous parents is  3:1.

In biology, a monohybrid cross is a cross between two organisms involving only one trait. Recall that genes occur in pairs called alleles, the expressed traits of individuals depends on the dominant (expressed) and recessive genes in the alleles.

Two heterozygous parents may be shown as Tt. The gene T is dominant while the gene t is recessive. We can see that three of the  offspring has the dominant T gene hence they will express the trait represented by T. Only one organism will express the trait represent by t. Therefore, the phenotypic ratio is 3:1.

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The phenotypic ratio of a monohybrid cross between two heterozygous parents is 9:3:3:1

1. dermis

2. chemical

3. urine

4. viruses

5. antibodies

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).