To which group on the periodic table does radon belong?

Why do oceanic plates tend to subduction when colliding with a continental plate

Which of the following types of stars are dim but can have high surface temperatures? giants main sequence stars supergiants dwarfs

Match the correct terms to their descriptions a system in which only energy but not matter is exchanged frozen water in snow part of geosphere that includes only soil a thin layer between the troposphere and the stratosphere cryosphere tropopause closed system pedosphere