Original: Endolith : An organism that lives in microscopic spaces within rocks , such as pores between aggregate grains ; these may also be called cryptoendoliths , a term that also includes organisms populating fissures , aquifers , and faults filled with groundwater in the deep subsurface .
Simplified: Endoliths : An organism that lives in microscopic spaces within rocks , fissures , aquifers , and faults filled with groundwater in the deep subsurface