The two most common elements in the Universe, and in most stars are - in that order - hydrogen and helium (elements #1 and #2).
The two most common ones are hydrogen and helium gas
Hydrogen and helium are the most abundant elements in stars.
Oxygen and silicon are the two most abundant elements found in the most common minerals. The most common minerals found on Earth are silicates.
Hydrogen and Helium.
Hydrogen and Helium are the two most common elements in the universe.
Hydrogen and helium.
Oxygen & Silicone.
Basically all of them. However, most stars contain large amounts of hydrogen (since that's the most common element in the Universe), as well as helium, as well as smaller amounts of other elements.
This question depends on what importance is being assigned. The most common dissolved ions (elemental atoms do not dissolve) are sodium and chloride, but they are many other important elements found in sea water.
Hydrogen, followed by helium.
Hydrogen and helium.
oxygen and silicon