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.
In traditional Jewish wedding ceremonies, the ring is placed on the index finger, but other traditions record placing it on the middle finger or the thumb, most commonly in recent times. Today, the ring usually is moved to the ring finger after the ceremony. Some Jewish grooms have adopted wearing a wedding ring.