The carbon in the gas cloud later formed part of some stars. No stars identified to date are as old as the gas cloud. The gas cloud also contained hydrogen and helium. Some stars were formed before the universe was two billion years old.
The early universe contained only the lightest elements, hydrogen and helium. Heavier elements, such as carbon, form only in nuclear reactions in stars and are dispersed when the stars explode. A recently discovered gas cloud contained carbon several billion years ago, when the universe was no more than two billion years old.
If the statements above are true, which of the following must, on the basis of them, also be true?