1:  State what "emission" means in the context of an atom's electronic energy levels, do so by stating what form of energy is involved and what change occurs when this energy is released. describe why all stars produce absorption spectra, despite the fact that their light originates in a hot & dense core. 

 2: Explain why wavelengths of light are compressed/stretched when the object producing the light moves towards/away from you. Relate your explanation to the speed of light, c.