Q. First cellular forms of life on earth appeared
Solution:
Origin of universe 20 billion years ago Origin of earth 4.5 billion years ago First life 4 billion years ago Origin of First non-cellular forms of life 3 billion years ago Origin of First cellular form of life (probably single-cells) 2 billion years ago
| Origin of universe | 20 billion years ago |
| Origin of earth | 4.5 billion years ago |
| First life | 4 billion years ago |
| Origin of First non-cellular forms of life | 3 billion years ago |
| Origin of First cellular form of life (probably single-cells) | 2 billion years ago |