These three members of the noble gas family all have one property in common because they are gases at room temperature. that is they

The members of 18 group of periodic table like He, Ne, Ar, Kr, Xe, and radon, belongs to the noble gas family. They are compressible, relatively dense and have no definite shape but have definite volume.

definite volume.

Explanation:

The members of the noble gas family like  He, Ne, Ar, Kr, Xe, and radon, all have some in common that is they are colorless or odourless, very unreactive gases and non-metals. They are gases at room temperature. That is they are  compressible, relatively dense and have no definite shape but have definite volume.

Noble gases are the least reactive gases in the periodic table because they have a complete valence shell electrons. These have high ionization enthalpies, low boiling points and negligible electronegativities that's why these are gases at room temperature.        

substitution is the answer in this case

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.