What is the most abundant element in the Universe?

The most abundant element in the Universe is Hydrogen. Here are the steps to understand why:

1. The Universe is composed of many elements, but the most abundant of these is Hydrogen.
2. Hydrogen makes up about 75% of the elemental mass of the Universe. This is because it is the lightest and simplest element, consisting of one proton and one electron.
3. The abundance of Hydrogen in the Universe is a result of the Big Bang theory. According to this theory, the Universe began as a very hot, dense point nearly 13.8 billion years ago. As the Universe expanded and cooled, it created Hydrogen, along with Helium and small amounts of Lithium.
4. Today, Hydrogen is found in abundance in stars and gas giant planets. During the process of nuclear fusion, stars convert Hydrogen into Helium, releasing a large amount of energy in the process. This is what makes stars shine.
5. Therefore, due to its simplicity, lightness, and the processes of the Big Bang and stellar nucleosynthesis, Hydrogen is the most abundant element in the Universe.