When is the earliest that functional ribosomes could have been found?
(A) Between 4 billion and 3.5 billion years ago
(B) Between 3.5 billion and 3.25 billion years ago
(C) Between 3.25 billion and 3 billion years ago
(D) Between 3 billion years ago and the present

It is difficult to determine exactly how life began. Answer the following questions as if the following data had been collected billions of years ago.

Transcribed Image Text:

Atmospheric carbon dioxide Atmospheric oxygen RNA Protein DNA Life 4 billion years ago Present 3.5 billion years ago Present 3.25 billion years ago Present Absent Absent Absent Absent Absent Absent Present Absent Present Present Absent Absent Present Present Present 3 billion years ago Present Present Present Present Present Present