Which characteristic is often described as changeable?

The characteristic that is often described as changeable is facial hair. This is because individuals have the ability to grow, trim, or remove facial hair as they choose. Unlike physical attributes such as race, height, or complexion, which are generally fixed and not easily altered, facial hair can be styled and changed frequently based on personal preference or grooming habits. This adaptability makes facial hair a unique characteristic that regularly shifts and can significantly alter someone's appearance based on individual choices.

In contrast, race is a biological and sociocultural classification that typically does not change. Height is a fixed physical attribute determined by genetics, and while complexion can change due to factors like sun exposure or age, it remains more constant than facial hair.