Because in our universe they are the simplest.
Hydrogen and helium are the first elements produced in the universe after the big-bang.
Helium is the most abundant of the Noble gases in the universe.
These gases are hydrogen and helium.
Hydrogen and Helium gases make up the universe.
The two main gases that make up a young star are hydrogen and helium. These elements were formed during the Big Bang and are the most abundant elements in the universe.
Roughly 98% of the solar nebula's mass consisted of hydrogen and helium gases. These two elements are the most abundant in the universe and are the primary components of stars like our sun.
They are primordially gases.
Hydrogen and helium are the two main gases in the Universe.
The major gases in Neptune's atmosphere are hydrogen, helium, and methane. Hydrogen and helium are the most abundant gases, with methane making up a smaller but still significant proportion.
This gas is hydrogen.
Many gases are present in the universe, but the most abundant is hydrogen
Most of the universe is made up of hydrogen gas, followed by helium. These two gases are the most abundant elements in the universe and can be found in stars, galaxies, and interstellar space.