extra questions on oxygen cycle and ozone layer class 9 maximum 10 question
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Answers
Explanation:
As we all know, the air is a mixture of gases. The air in the atmosphere is composed of different gases, namely nitrogen (78%), oxygen (21%), argon and other trace gases (1%).
According to Earth’s history, oxygen gas was first introduced by cyanobacteria through the process of photosynthesis. Earlier, around 4.6 billion years ago, there was no life on planet earth because the atmosphere was devoid of oxygen. Later, there was a gradual increase in the oxygen levels and by the Carboniferous Period- 299 million years ago, oxygen reached the levels that were similar to today’s estimates.
Today, oxygen is freely available in the air, and also dissolved in water. It is the second most abundant gas present in the atmosphere and also the most common element of the human body. It plays an essential role in most life forms on Earth and also serves as an essential element in biomolecules like proteins, and nucleic acids.
Read on to explore more about oxygen, its uses, production, and how it is recycled in a cyclic pattern.