The spectrum of an excited gas is a series of discrete lines becausea. in multielectron atoms, each electron emits a certain, unique wavelength. b. different atoms in the gas have different ionization states. c. other wavelengths are absorbed by the gas. d. electrons exist in quantized energy states, and only certain transitions are possible

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods