Why do old books turn yellow?
Show answer & explanation
Answer: Paper oxidizes with age
Paper oxidizes with age ✓ — Correct! Paper contains lignin which oxidizes when exposed to air and light, creating yellow-brown compounds. Acid in cheaper paper accelerates this. That's why archival paper is acid-free!
Ink fades and spreads — Wrong. Ink behavior doesn't cause paper yellowing. The paper itself chemically changes.
Mold grows on pages — Wrong. Mold causes different damage patterns, not uniform yellowing.