Approximately When Did Primitive Cells First Appear on Earth

Question

Approximately when did primitive cells first appear on Earth?
A)1 billion years ago
B)2 billion years ago
C)2.5 billion years ago
D)3 billion years ago
E)3.8 billion years ago

Accepted Answer

The oldest known fossils of primitive cells, specifically of cyanobacteria, date back to 3.5 billion years ago. Therefore, it is believed that primitive cells first appeared on Earth even earlier, around 3.8 billion years ago. Option E is the closest approximation to that time period.