A 3-inch plant was crossed with a 15-inch plant, and all F₁ plants were 9 inches. The F₂ plants exhibited a 'normal distribution,' with heights of 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 inches.
What ratio will constitute the 'normal distribution' in the F₂?

Normal distribution is a statistical concept where data points are symmetrically distributed around a mean, forming a bell-shaped curve. In genetics, traits often follow this distribution when influenced by multiple genes, leading to a range of phenotypes. The heights of the F₂ plants in this scenario suggest that multiple alleles contribute to the trait, resulting in a continuous variation.

Phenotypic ratio refers to the relative frequency of different phenotypes in a population. In the context of the F₂ generation, the ratio of plant heights can be analyzed to determine how traits are inherited. For traits governed by multiple alleles, the phenotypic ratio can often approximate a specific pattern, such as 1:2:1 or 9:3:3:1, depending on the genetic interactions.

Quantitative traits are characteristics that are influenced by multiple genes and environmental factors, resulting in a continuous range of phenotypes. In this case, the plant heights represent a quantitative trait, as they vary from 3 to 15 inches. Understanding how these traits are inherited and expressed is crucial for predicting the distribution of phenotypes in the F₂ generation.