Multiple choice general knowledge

How much Carbon dioxide (CO2) is in Earth's atmosphere today?

  1. 10% or greater

  2. less than 1/10th of 1%

  3. 2% to 10%

  4. 1%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Carbon dioxide makes up about 0.04% (400 parts per million) of Earth's atmosphere, which is less than 1/10th of 1%. Despite this small concentration, CO2 is the most significant greenhouse gas emitted by human activities and is the primary driver of recent global warming. Other gases like nitrogen (78%) and oxygen (21%) make up the vast majority of our atmosphere.

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