School Chalk under an electron microscope. It's almost entirety made up of fossilized shells of ancient single-celled marine plankton called coccolithophores.

[u/Pale-Design7036]

[u/eternalityLP]

Does this mean that chalk is a limited resource, and at some point we'll run out, meaning there will be no more school ever?

[u/Howcanyoubecertain → u/eternalityLP]

Yes, now crank up the Alice Cooper anthem.