Phanerozoic is the eon which geologic time scale means visable life.
Most scientists agree that there are 3 eras for every eon.
git a life a
The Proterozoic is a geological eon representing the time just before the proliferation of complex life on Earth. Most life forms at the time were single celled organisms.
the eon that constitutes the earlier (or middle) part of the Precambrian, in which there was no life on earth. It precedes the Proterozoic eon. Also called azoic .
Phanerozoic
Phanerozoic
no
archean eon
5th Edit: The ancient Greeks referred to an eon as being an eternity, so by that definition, we would be in the one and only eon, but in geology, an eon amounts to about 1 billion years, making the Earth be 4.6 eons old, so, the answer would either be the first eon, or the 5th eon. Depends on how you look at it.
We currently live in the Phanerozoic eon, which began around 541 million years ago and is marked by the diversification of multicellular life. The Phanerozoic eon is divided into three eras: the Paleozoic, Mesozoic, and Cenozoic.
I don't know the plural of eon but the answer is more than 1 eon