This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine System, Subject name: Physiology
Nonshivering thermogenesis in adults is due to: 
Select and explain. 
A. Thyroid hormone, B. Brown fat between the shoulders, C. Noradrenaline, D. Muscle metabolism
A: Thyroid hormone
Answer: A: Thyroid hormone 
Explanation: Thyroid hormone Increases the BMR which is responsible for Non-shivering thermogenesis in adults. In children & Infants Brown fat is responsible for thermogenesis. Shivering thermogenesis is by muscle metabolism, heat is produced by muscle contraction.