In view of bohrs explanation of the link between emission spectra and electron transitions, answer more fully the question, what does each line represent in the emission and absorption spectra of an incandescent gas? i have a general idea but i cant think of enough to meet the word requirement.

According to Bohr's explanation the lines of an emission or absorption spectra of an incandescent gas are representative of the energy radiated from the hydrogen atom. When an electron moves from one energy level to another lower level it releases, or radiates, the differences in energy between the two separate energy levels. This released energy, as mentioned, is displayed as a bright-line. Each of these individual lines also represent a different color of light, and therefore a different wavelength and frequency. That's what I have so far, but it still isn't long enough.

it's c. elements are placed in rows based on how may valencies electrons have.