What is the primary function of the Sebaceous gland?

The primary function of the sebaceous gland is to secrete oil, known as sebum, which serves to lubricate both the hair and skin. This oil plays a crucial role in maintaining skin hydration, protecting against dryness, and providing a barrier against certain bacteria. Sebum also gives hair a healthy shine and can help to prevent hair from becoming brittle and breaking.

While the other options mention functions that are important for hair and scalp health, they do not accurately represent the primary role of the sebaceous gland. For instance, cooling the scalp is not a function of the sebaceous gland; rather, it is primarily the role of sweat glands. Although sebaceous glands contribute to a healthy environment for hair growth, they do not directly produce hair themselves. Thus, the correct answer highlights the essential role of these glands in surface lubrication and overall skin and hair health.