User: From the passage provided, how is the instrument called the "rubab" made?
Assistant: The body of the rubab is carved out of a single piece of wood, with a head covering a hollow bowl which provides the sound-chamber. The bridge sits on the skin and is held in position by the tension of the strings. It has three melody strings tuned in fourths, two or three drone strings and up to 15 sympathetic strings. The instrument is traditionally made from the trunk of a mulberry tree, the head from an animal skin such as goat, and the strings from the intestines of young goats (gut) or nylon.