During the _______ period of the _______ era, atmospheric O₂ level was almost equal to the present level, and multicellular life forms were abundant and diverse in the sea (but nowhere to be found, yet, on land).

Question

Quizplus · Accepted Answer

The statement mentions the existence of multicellular life forms in the sea but not on land, which is a characteristic of the Cambrian period of the Paleozoic era. Additionally, during the Cambrian period, atmospheric oxygen levels were similar to the present day.

During the _______ Period of the _______ Era, Atmospheric O2

During the _ Period of the _ Era, Atmospheric O₂