Which of the following is a core responsibility of an esthetician?

An esthetician's core responsibility centers around providing skin care treatments and makeup application. This role involves assessing clients' skin conditions, recommending appropriate treatments and products, and performing various facials, peels, and other skin care procedures. Additionally, estheticians often assist clients in selecting makeup products and applying them effectively, highlighting their expertise in enhancing skin appearance.

The other options fall outside the typical scope of an esthetician's duties. Performing surgery for cosmetic enhancements is a responsibility reserved for licensed medical professionals, such as plastic surgeons. Conducting psychological evaluations requires specialized training in psychology, which is not part of an esthetician's education or practice. Designing marketing strategies for beauty products is primarily a business and marketing function, rather than a direct service provided to clients in a clinical or spa setting. Thus, providing skin care treatments and makeup application represents the essential and recognized functions of an esthetician.