24. History of Life on Earth
History of Life on Earth
24. History of Life on Earth History of Life on Earth
32PRACTICE PROBLEM
About 3 billion years ago, Earth was completely void of oxygen. Oxygen levels gradually increased as photosynthetic bacteria multiplied over time. Which of the following microscopic bacteria performed this photosynthetic role that allowed the establishment of more complex organisms on the Earth's surface?
About 3 billion years ago, Earth was completely void of oxygen. Oxygen levels gradually increased as photosynthetic bacteria multiplied over time. Which of the following microscopic bacteria performed this photosynthetic role that allowed the establishment of more complex organisms on the Earth's surface?