GEO- which of the earths spheres is unique to earth ( no other planets have this sphere)?

The spheres are the four subsystems that make up the planet Earth. They are called spheres because they are round, just like the Earth. The four spheres are the geosphere (all the rock on Earth), hydrosphere (all the water on Earth), atmosphere (all the gases surrounding Earth), and biosphere (all the living things on Earth).

Hope this helps :)

polar areas, such as antarctica or the south pole.

the rub-al-khali is also known as the arabian desert and the "empty quarter"