Select the best answer
Which of the following events define the Proterozoic eon?
-eukaryotic cells first seen
-stable continents
-first bacterial fossils
-Cambrian explosion
-oxygen builds up in atmosphere
Which of the following events define the Proterozoic eon?
-eukaryotic cells first seen
-stable continents
-first bacterial fossils
-Cambrian explosion
-oxygen builds up in atmosphere