Sebaceous glands are tiny oil-producing glands present in the skin.
They secrete sebum, which lubricates and protects the skin and hair from drying out.
If the sebaceous glands produce less oil, the skin becomes dry and rough due to lack of moisture and lubrication.
Sweat glands help in cooling the body by producing sweat but do not lubricate the skin.
Apocrine glands are a type of sweat gland mainly found in areas like underarms and are linked to body odor.
Thyroid glands are endocrine glands that regulate metabolism but do not produce skin oils.
Therefore, a lack of lubrication from sebaceous glands causes dry skin.