<u>Answer:</u>
<em>Hydrogen and ozone are both examples of trace gases.
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<u>Explanation:</u>
Trace gases are present in minor quantities in the <em>earth’s atmosphere and all the gases except nitrogen, oxygen and argon </em>which make up the major portion of earth’s atmosphere are considered trace gases.
The respective percentages of nitrogen, oxygen and argon in the atmosphere are<em> 78.1%, 20.9% and 0.934%.</em> The process that produce trace gases is called source and the process that removes trace gas from the <em>atmosphere is called sink.
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<em>Some other examples of trace gases are carbon dioxide, neon, helium etc.
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