Question

7
which of the choices below is one of the primary gases found in the atmosphere?
○ a. carbon dioxide
○ b. oxygen
○ c. argon
○ d. helium

Explanation:

The Earth's atmosphere is mainly composed of nitrogen (about 78%) and oxygen (about 21%). Carbon dioxide, argon, and helium are present in much smaller amounts. Among the options, oxygen is a primary gas in the atmosphere.

Answer:

B. Oxygen