These prokaryotes are usually NOT found in extreme environments such as thermal vents on the bottom of the ocean floor.

Prokaryotic organisms not usually found in extreme conditions or environments -such as thermal vents on the bottom of the ocean floor- are bacteria.

Explanation:

The known prokaryotic organisms are bacteria and archaea, which share some similarities but are considered functionally different, which is why they are classified in different domains.

One of the differences between bacteria and archaea is that archaea are considered extremophiles, due to their ability to tolerate and survive in environments with adverse conditions, such as high temperatures and pressure, high acidity, alkalinity or salinity. The vast majority of bacteria could not tolerate extreme conditions.

i'd say that the moon rock is about 2.2 billion years old.