What substance do sebaceous glands produce?

Sebaceous glands are specialized glands in the skin that are responsible for producing sebum, an oily substance. Sebum plays a crucial role in maintaining skin health by providing moisture, reducing water loss, and protecting the skin from microbial infection. It acts as a natural lubricant and helps to keep the skin soft and supple.

Collagen, keratin, and melanin are important substances found in the skin but are produced by different mechanisms and cells. Collagen is a protein that provides strength and structure to the skin, mainly produced by fibroblasts. Keratin is a fibrous protein found in the outer layer of the skin, produced by keratinocytes, and is essential for the protective barrier function. Melanin, the pigment responsible for skin color, is produced by melanocytes and protects against UV radiation.

Understanding the specific roles of these substances and the glands that produce them highlights the importance of sebum in overall skin health, making it the correct answer in this context.