What is an example of a trait that demonstrates polygenic inheritance?

Polygenic inheritance involves multiple genes contributing to a single trait, resulting in a continuous range of phenotypes rather than distinct categories. Skin color in humans is a classic example of polygenic inheritance, as it is influenced by several genes that affect the type and amount of melanin produced, leading to a broad spectrum of skin tones. Each of these genes adds a small amount to the overall phenotype, which is why skin color can vary significantly among individuals.

In contrast, traits like flower color in pea plants or blood type in humans are influenced by single genes or a limited number of genes with clear and distinct categories, which do not fit the definition of polygenic traits. Color blindness, while influenced by specific genetic factors, typically follows a simpler inheritance pattern rather than the continuous variation seen in polygenic traits.