Final answer:
The substance secreted by sebaceous glands is sebum, an oily substance that helps to waterproof and lubricate the skin and hair, while also providing antibacterial properties.
Step-by-step explanation:
The substance secreted by the sebaceous glands is an oily substance called sebum. Sebum plays a crucial role in maintaining the health of your skin and hair. It waterproofs and lubricates the skin and hair, helping to prevent them from drying out. Additionally, the fatty acids in sebum possess antibacterial properties, which help in inhibiting the growth of microorganisms on the skin. Sebaceous glands, which are a type of holocrine gland, are found throughout the skin, except on the palms of the hands and soles of the feet. These glands are commonly associated with hair follicles and discharge their oily contents to the skin's surface alongside hair.