What percentage of normal matter is made up of Hydrogen?

The correct answer, which indicates that approximately 75% of normal matter in the universe is made up of hydrogen, highlights the significant role hydrogen plays in the composition of the universe. Hydrogen is the most abundant chemical element, forming the core of stars and being a primary building block of more complex elements through nuclear fusion processes.

In the context of the universe, hydrogen accounts for a substantial portion of normal (baryonic) matter. This amount is especially relevant because, during the early stages of the universe's formation, hydrogen was one of the first elements to form as the universe cooled down after the Big Bang. The remaining percentage is made up of other elements such as helium and a small fraction of heavier elements.

The other choices do not accurately represent the distribution of elements in the universe. Thus, the figure of around 75% highlights hydrogen's dominance in the makeup of normal matter.