Which of the following gases is found in very little qantity in the atmosphere?

Analyze the question: We need the gas that occurs in the smallest amount in the atmosphere among the four options.

Concept: Composition of dry air (by volume)

• Nitrogen: about 78.08%
• Oxygen: about 20.95%
• Argon: about 0.93%
• Carbon dioxide: about 0.04% (roughly 0.04%, or about 420 ppm)
• Others (neon, helium, methane, etc.): trace amounts

Step-by-step solution:

1. Nitrogen (C) is the most abundant gas, so it is not the answer.
2. Oxygen (D) is the second most abundant, at about 21%, so it is not the answer.
3. Argon (A) is third, at about 0.93%. That is small, but it is still more than carbon dioxide.
4. Carbon dioxide (B) is only about 0.04%, which is the smallest of the four.

So the gas found in very little quantity is carbon dioxide.

Tip: Remember the order of abundance with the phrase "No One Argues Constantly": Nitrogen, Oxygen, Argon, Carbon dioxide. The order goes from most to least abundant. Even though CO₂ is present in tiny amounts, it is very important. Plants need it for photosynthesis, and it contributes to the greenhouse effect.