Where does the exosphere play in the layers

The crust of earth may a- continets and ocean floors. b-continents only. c-layers of sedimentary rocks and continents. d-all of the above

What can be found in the ionosphere

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?