Question

why is a phenotypic ratio analysis useful?
it shows how to change an organisms traits in a lab.
it proves that all traits are inherited equally from each parent.
it helps determine the genotype of the parental generation.
it tells the exact number of chromosomes an organism has.

Explanation:

• Option 1: Phenotypic ratio analysis doesn't show how to change traits in a lab. Eliminate.
• Option 2: Not all traits are inherited equally (e.g., sex - linked traits), so this is incorrect. Eliminate.
• Option 3: By analyzing the phenotypic ratios of offspring, we can infer the possible genotypes of the parents. For example, in a monohybrid cross, a 3:1 phenotypic ratio in F2 suggests the parental generation was homozygous dominant and homozygous recessive. This is correct.
• Option 4: Phenotypic ratio analysis has nothing to do with determining the number of chromosomes. Eliminate.

Answer:

C. It helps determine the genotype of the parental generation.