Eli5: Was all the organic matter in the soil once alive?

Question

Title says it all, is the organic part of our planet’s ground, the dirt/soil all of biological origin be it leaves or waste or flesh of plants and animals over many many many years? Or are there other ways some is formed through geological methods?

In: 1

Answer 1

TaleThick answered it best, but basically any blackness (carbon) you see in the soil was once alive, and probably still is habitat for millions of microbes.