This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of skin, Subject name: Dental
Acne vulgaris involves- 
Select and explain. 
A. Sweat glands, B. Sebaceous gland, C. Hair follicles, D. Ceruminous glands
B: Sebaceous gland
Answer: B: Sebaceous gland 
Explanation: Acne vulgaris is a disorder of sebaceous glands. Acne vulgaris is a skin condition that occurs when hair follicles are blocked with dead skin cells, bacteria, and oil (sebum). ... Causes Hormonal changes in pregnancy or from the menstrual cycle. Some medications. Ceain cosmetics and lotions. High humidity and sweating. Polycystic ovary syndrome (PCOS) Ref Harrison20th edition pg 1234