sentence: Many trees produce resin, but usually it is broken down by physical and biological process.
sentences_before: To end up as amber, the starting resin must resist decay.
sentences_after: Exposure to weather tends to disintegrate resin, assisted by microorganisms such as bacteria and fungi. For resin to survive long enough to become amber, it must resist such forces, or be produced under conditions that exclude them. Life in amber'.
concept_name: tree
headings: Amber Amber in geology
categories: Minerals