What can a Dark Line tell us about?

[Tiny]

Homework question ><
When you see a dark line in the solar spectrum what does that mean or what does it trying to tell us? I know this is simple, but its hard for a beginner ><

[TheThorn]

A dark line in the solar spectrum tells us that there is something between us and the sun that is absorbing that particular frequency of light. By lab testing we can determine what particular frequencies of light are absorbed by each element, and that way we can figure out wxactly which element it is that must be the culprit.