What is the primary function of sebum?

Sebum is an oily substance produced by sebaceous glands in the skin, and its primary function is to lubricate and protect the skin. This natural oil helps maintain moisture levels, preventing the skin from becoming dry and brittle. It acts as a barrier against environmental factors, including bacteria and pollutants, which can cause skin irritation or infections. By keeping the skin hydrated and providing a protective layer, sebum plays a crucial role in maintaining overall skin health and appearance.

While other options like circulating blood, aiding in digestion, and filtering air involve important physiological functions, they are not related to sebum's role in skin care. Sebum specifically serves the unique purpose of maintaining skin integrity and health, making its protective and lubricating properties essential for the skin's function.