Which of the following is an example of a skin condition studied in dermatology?

Acne is classified as a skin condition studied in dermatology because it involves specific changes and issues related to the skin's health and function. Dermatology focuses on identifying, diagnosing, and treating various skin-related ailments, and acne is one of the most common conditions encountered. It arises from the clogging of hair follicles with oil and dead skin cells, leading to the formation of pimples, cysts, and other lesions.

In contrast, nutrition pertains to dietary habits and is more related to overall health than to specific skin conditions, making it outside the primary focus of dermatology. Color theory involves the study of colors and their impact on aesthetics, not specifically on skin conditions. Ingredient safety addresses the safety and efficacy of products used on the skin but does not define a condition in itself. Hence, acne stands as a clear example of a condition studied rigorously in dermatology, focusing on its causes, symptoms, and treatment options.