Final answer:
Characteristics that are influenced by many genes and environmental factors are referred to as multifactorial. These traits follow polygenic inheritance and can have a broad range of phenotypes, exemplified by human height, skin color, and eye color.
Step-by-step explanation:
Characteristics affected by many genes and environmental factors are called multifactorial. Traits like height, skin color, and eye color are examples of multifactorial traits because their expression is the result of multiple genes working together with various environmental influences. This type of inheritance, where multiple genes influence a single trait, is known as polygenic inheritance. Due to multiple genes contributing, these characteristics can have a wide range of phenotypes and express themselves in a continuous spectrum rather than discrete categories, like Mendelian traits.
Multifactorial traits are contrasted with Mendelian traits which imply that every characteristic is distinctly controlled by a single gene, which is not the case with most complex traits observed in humans and other organisms. With multifactorial traits such as adult height, numerous phenotypes can be seen due to the combination of various alleles across different genes.