Young stars are made of dust and gas and old stars are only made of dust?
The stars are made up mostly of hydrogen and helium, and only a small percentage of everything else: water, carbon, iron, etc. “Remaining all” is all made from mainly space dust, so we can generally say that all stars are comprised of gas and dust; however, stars are so high in temperature that all the dust in a star could have evaporated during its formation, so all matter in any star is now completely gaseous.