Final answer:
Marcus's dimples are part of his phenotype, used in art to convey personal qualities like gravitas and virtus. This portrayal reflected societal values in the Late Roman Republic, providing insight into the subject's character based on physical traits.
Step-by-step explanation:
The physical characteristics such as the dimples evident in a person's cheeks are part of Marcus's phenotype. This term refers to the observable physical traits of an individual, which result from the interaction of genetics and the environment. In the context of the Late Roman Republic, physical traits portrayed in art, such as the wrinkled and sagging features of a Roman patrician, were designed to convey gravitas and virtus. The physical markers were seen as a visual testament to a public figure's serious-mindedness and virtue, qualities that aligned with their social and political endeavors.