photosynthsis
oxygen
oxygen
no
oxygen
It is believed that the early Earth's atmosphere did not contain significant amounts of oxygen. Oxygen began to accumulate in the atmosphere around 2.4 billion years ago due to the emergence of photosynthetic organisms.
Earth's early atmosphere was primarily composed of carbon dioxide. Early bacteria used carbon dioxide as a source of fuel and as a result produced oxygen.
The primary sources of oxygen in Earth's early atmosphere were likely photosynthetic organisms like cyanobacteria, which began producing oxygen as a byproduct of photosynthesis. Over time, this oxygen built up in the atmosphere, leading to the development of oxygen-rich conditions on Earth.
Oxygen (O2) was not present in early Earth's reducing atmosphere. It only became abundant in the atmosphere due to the photosynthetic activity of cyanobacteria and other early organisms.
photosynthetic organisms, like cyanobacteria, which produced oxygen as a byproduct of photosynthesis. This led to the increase in atmospheric oxygen levels, changing the composition of Earth's early atmosphere.
Oxygen was added to Earth's atmosphere through the process of photosynthesis by early photosynthetic organisms like cyanobacteria. These organisms released oxygen as a byproduct, which accumulated over millions of years and eventually led to the oxygen-rich atmosphere we have today.
Oxygen was the important element missing in Earth's early atmosphere. It was only produced later by photosynthetic organisms.
They look at the mineral composition of the rocks. There are some minerals that can only form in the presence of oxygen.