Which elements make up empty space in the universe select two options

Hydrogen and Helium (among many others present)    hope this helps!    :)

Explanation:

Generally speaking the universe consists of rather large amounts of empty spaces, also known as voids. As we know, our total existance and everything in it (i.e. the Universe) is mostly made of significantly small particles (also known as atoms), that are energy filled. However, even among those particles we watch/ notice/ celebrate/ obey large empty spaces. You can think of it as a 'vacuum' that consists of elements such as hydrogen and helium plasma, many particles of low density levels, along with (universe-related) rays, neutrinos, dust but also (related to electricity producing magnetic fields) radiation and magnetic fields. From all these elements present, scientists figure out that the most most important are in fact the Hydrogen and Helium.

It has been decided that in the Universe, more than 99% of the (universe-related) matter is in fact an empty space!!