It's found in many English words related to life, like:
* Biology: the study of life
* Biosphere: the part of Earth where life exists
* Biopsy: the removal of tissue for examination
* Biography: an account of someone's life
* Biotechnology: the use of living organisms in technology
* Biodegradable: capable of being broken down by living organisms
You can also see the root "bio" in various prefixes and suffixes:
* Bio-: meaning "life" (biochemistry, bioluminescence)
* -biotic: meaning "related to life" (abiotic, biotic)