Carl Sagan - the same Carl Sagan who persuaded NASA scientists to turn Voyager around and take the 'Pale Blue Dot' photo we mentioned earlier, gave a number of lectures in the early 1980s, during which he stated that human beings are composed of elements that originated within the stars themselves. And he's mostly right.
Originally, the universe was composed only of hydrogen and helium. Carbon - the base material which humans are made of- as well as nitrogen and oxygen - were created much later, in the hearts of stars. As these stars died, they exploded, expelling debris across space as a gas. Among these gases are element that eventually settled and became planets, and the building blocks of life itself. Without the birth and death of those early stars some 4.6 billion years ago, the conditions necessary for life to begin would never have been created, and you wouldn't be here right now to read this article. As Sagan himself said, "We're all made of star stuff".