The discoveries of niels bohr were: a. orbits of electrons. b. charge on the electron. c. quantum energy emissions. d. static electricity

The correct answer are A. orbits of electrons and C. quantum energy emissions.

Neil Bohr was the first who explained that electrons moves around the nucleus in the separate orbits or shells in an atom. He also discovered that electrons can only be in a particular orbits of fixed energy and when electrons allowed to jump from one orbit to another, they absorbed or emitted electromagnetic radiation.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).