The product of sweat glands is sweat – a colorless, brackish-tasting liquid (it contains NaCl, urea, uric acid, ammonia, and some amino acids). Then, metabolic products are secreted from the body, and thermoregulation also occurs (lowering body temperature when sweat evaporates). The sebaceous glands secrete a secret (sebum) consisting of the decay products of epithelial cells, vitamins A, D, etc. Sebum lubricates growing hair and skin, protecting them from drying and wetting with water. Thanks to grease, the hair looks elastic and shiny.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.