What is a specific characteristic that varies from one individual to another called?

A specific characteristic that varies from one individual to another is called a trait. Traits can include variations in physical features such as eye color, hair color, height, and various behaviors. These differences arise due to genetic variations and environmental influences. Each trait is influenced by one or more genes, but the term "trait" specifically refers to the expressed characteristic that can be observed and measured in individuals.

In the context of genetics, understanding traits is essential as they illustrate how genetic information is expressed in the physical attributes of an organism. This concept is foundational in studies of inheritance and variation among species. Other terms like gene, protein, and chromosome refer to the underlying biological structures and functions rather than the observable characteristics themselves, making "trait" the most appropriate description for variability between individuals.