Oxygen is the most abundant element in the Earth’s crust and oceans.
Through photosynthesis, plants absorb carbon dioxide and release oxygen.
Humans and animals need to inhale oxygen to sustain life.
One of the breakthroughs in human history is the use of fire, which comes from the chemical reaction between inflammable materials and oxygen.
The ozone layer in the Earth’s stratosphere absorbs most of the Sun's ultraviolet radiation, keeping us safe.
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