Earth formed about 4.5 billion years ago, and life appeared roughly 50…

Question

Earth formed about 4.5 billion years ago, and life appeared roughly 500 million years later. The first cellular forms of life, however, did not appear until about:

Accepted Answer

C. {'text': '2000 million years ago, as the first single-celled life', 'label': 'C'}

Per the chapter, life appeared about 4 billion years ago in the form of giant non-cellular molecules (RNA, protein, polysaccharides) around 3 billion years back, but the first cellular forms of life did not possibly originate till about 2000 million years ago.

Answer

{'text': '4 billion years ago, immediately after earth cooled', 'label': 'A'}

Answer

{'text': '3 billion years ago, with the first non-cellular giants', 'label': 'B'}

Answer

{'text': '500 million years ago, alongside the first invertebrates', 'label': 'D'}