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! :)
its c, someone reported my answer and it got taken down last time
One theme from Rikki Tikki Tavi would be courage. Rikki has to fight<span> two cobras, Nag and Nagaina, to protect his garden and Teddy. He is frightened of them because they are stronger and bigger than he is, but he overcomes his fear and fights them anyway.</span>
Kinship refers to a social bond based on marriage or adoption
