Atmospheric oxygen is a result of photosynthesis by plants (including cyanobacteria - blue -green algae - which was responsible for the initial conversion of earth 's atmosphere from its anoxic state) .
Photosynthesis is carried out in plants. It employs energy from the sun and naturally occurring water and carbon dioxide to produce sugar and oxygen gas. The oxygen is released to the atmosphere, and the sugar is formed into plant matter, which it eventually and is buried and turned into coal, oil and gas.
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 makes up about 21% of Earth's lower atmosphere by volume.
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.
Earths atmosphere is rich in Oxygen, some 21% of the air is Oxygen. There is oxygen on other planets, but the percentage comes nowhere close to this. The percentage of Oxygen in earths atmosphere is thought to have been much higher in the past, before animals were about, but after the arrival of plants.
The earths atmosphere is made up of 78% nitrogen and 21% oxygen
97%
no
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 gas
Free oxygen
Plants
oxygen
Nitrogen and oxygen,
no
mostly nitrogen with 21% oxygen
photosynthsis