The Carboniferous period, during which oxygen amounted to 35% of the atmosphere by volume (this was around 300 million years ago). Nowadays the amount is 20.95%.
Oxygen gas
Nitrogen and Oxygen
Yes. Earth's atmosphere is about 21% oxygen. Without it, the vast majority of life we see, including humans, could not exist.
Earths atmosphere is mostly nitrogen (78%) and Oxygen (21%).It is the oxygen that is the essential gas for breathing.
Oxygen was not found in the atmosphere of primitive Earth. It is so reactive that it became locked up in compounds at the time of Earths formation. These compounds were varied, but the bulk of them were mineral oxides, silicates, carbon dioxide and water. Free oxygen entered the atmosphere only after the development of blue-green algae, which produced oxygen from carbon dioxide.
The element "Oxygen".
Oxygen makes up about 21% of Earth's lower atmosphere by volume.
Oxygen was not present in the Earth's atmosphere 3.6 billion years ago. The atmosphere at that time was primarily composed of carbon dioxide, nitrogen, methane, and water vapor. Oxygen began to accumulate in the atmosphere around 2.5 billion years ago as a result of photosynthetic organisms.
The approximate percent of oxygen in Earth's lower atmosphere is around 20.95% by volume.
The approximate percentage of oxygen in Earth's lower atmosphere is around 21% by volume.
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.
The approximate percentage by volume of oxygen in Earth's atmosphere at location 2 is around 21%.
Oxygen accumulates in Earth's atmosphere from photosynthesis, where plants and algae convert carbon dioxide into oxygen. This process started with the emergence of photosynthetic organisms around 2.5 billion years ago, gradually increasing oxygen levels to the current 21 percent.
The earths atmosphere is made up of 78% nitrogen and 21% oxygen
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.
97%