Which chemical element is the lightest, but at the same time it is estimated to take up 3/4 of the Universe's mass?

Explanation

Hydrogen is a chemical element with symbol H and atomic number 1. Hydrogen is the lightest element on the periodic table. It is the most abundant chemical substance in the Universe, constituting roughly 75% of all mass. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned. In Greek, hydrogen means "water-former".