We don't have 100 years of data, but we do have 20 years of data, with data going back much farther through proxy data. We can create a pretty good guess back 100 years because we have records of CO2 since 1957, and better proxy records of CO2, which is strongly tied to oxygen.
Ozone in atmosphere acts as a shield. It protects us from UV rays of the sun.
the amount of animals breathing in the oxygen, and not enough plants.
No. While the concentration of oxygen in a cloud on Earth is much higher than it is in the sun, the total amount is much lower. A single cloud contains only a tiny portion of Earth's atmosphere, which is itself a tiny fraction of Earth's mass. The sun is about 330,000 times the mass of Earth and is about 1% oxygen, so even at such a low concentration, the mass of oxygen in the sun is about 3,300 times the total mass of Earth.
True. It's now over 400 ppm (parts per million) or 0.04%.
Ozone is a tri oxygen molecule. It is formed in a natural process by the action of UV light on oxygen molecule.
Approximately 20%.
Other planets do have oxygen, but not in as high of concentration as we have here on Earth.
precipitation
Oxygen and Nitrogen
78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide
Oxygen (~21%) is second to nitrogen (~78%) in the composition of Earth's atmosphere.
The atmosphere of Earth features oxygen and nitrogen. Small quantities of other gasses such as Argon can also be found throughout the air.
Because there are more volcanoes which bursts when our earth becomes warm and losses the atmospheric oxygen content.
It is an alkaline earth metal. It conducts heat and electricity. It reacts with atmospheric oxygen and forms oxide.
The Earth's atmosphere is made up primarily of Nitrogen, Oxygen and Argon. The atmosphere is 78% Nitrogen, 21% Oxygen and just less than 1% Argon. Small amounts of other gases are ever present.
Ozone in atmosphere acts as a shield. It protects us from UV rays of the sun.
the amount of animals breathing in the oxygen, and not enough plants.