Atom -> molecule - organelle - cell - tissue - organ - organ system - organism - population - community - ecosystem - biosphere
There’s more to this but that’s whether you require more or less of the list
Protozoans, bacteria, fungi... viruses are not organisms
Answer: Paleozoic
Explanation: The Paleozoic Era, which ran from about 542 million years ago to 251 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another plants became widespread. And the first vertebrate animals colonized land.
