Question

Scientists found _______ containing fossilized cyanobacteria. Oparin and Haldane hypothesized that life needed reducing environments initially. The ocean in the early ages was ______.

a. Rocks / Oxygenated
b. Sediments / Acidic
c. Sediments / Oxygenated
d. Rocks / Devoid of oxygen

Answer 1

Cyanobacteria, which produce oxygen as a by-product of photosynthesis, appeared within one billion years of Earth's formation, leading to the oxygenation of the atmosphere.

Step-by-step explanation:

d. For the first two billion years of Earth's existence, the atmosphere had no molecular oxygen. Thus, the first organisms were anaerobic. Cyanobacteria which produce oxygen as a by-product of photosynthesis, leading to the oxygenation of the atmosphere, appeared within one billion years of Earth's formation. From these organisms evolved phototrophic organisms.