Zoology - Evolution Question with Solution | TestHub

Big Bang theory explains the origin of universe, which occurred about$\text{20 billion}$or$\text{20000 million}$years ago. The origin of Earth occurred about$\text{4.5 billion}$or$\text{4500 million}$years ago. The first non cellular form of life was originated about$\text{3 billion}$or$\text{3000 million}$years ago.