In Comparing the Fraunhofer Lines with Light Emitted by Elements

In comparing the Fraunhofer lines with light emitted by elements in a flame, Bunsen and Kirchhoff demonstrated that _______.

A) atoms emit and absorb electromagnetic radiation at characteristic wavelengths.
B) the solar spectrum is continuous.
C) alkali metals absorb and emit the same wavelengths.
D) nuclear reactions are responsible for the absorption and emission of electromagnetic radiation.
E) the sun's composition is changing over time.