Brown adipose tissue is present in small mammals (e.g., mice) and in newborn humans. Most of it disappears in adult humans. The cells in both types of fat are called adipocytes although they differ in origin, structure, and function in the two types of tissue.
On the left hand, index finger. It's not the index finger you wear it on. Left hand, ring finger. The finger that you would wear a wedding ring on.
According to a tradition believed to have been derived from the Romans, the wedding ring is worn on the left hand ring finger because there was thought to be a vein in the finger, referred to as the 'Vena Amoris' or the 'Vein of Love' said to be directly connected to the heart. Therefore, the wedding ring is always worn in the left hand ring finger.