Books that are surrounded by oxygen will turn yellow, so basically, all books since oxygen is constantly surrounding us. Oxygen-rich conditions are very bad for paper, which gives them the yellow tiny. This is actually called lignin oxidation! Lignin oxidation gives it a yellow or brown colour as you said. Yellow comes first, then brown after.
I hope this helped a bit! :)
the answers are darkness and light
<span>traditional values versus contemporary values
loyalty to family versus loyalty to the state
maternal instincts versus paternal instincts
</span>
B: Until we are able to confirm whether or not the radio waves came from outside of this solar system
