title: Abundance of the chemical elements
context: The order of elements by volume-fraction (which is approximately molecular mole-fraction) in the atmosphere is nitrogen (78.1%), oxygen (20.9%),[14] argon (0.96%), followed by (in uncertain order) carbon and hydrogen because water vapor and carbon dioxide, which represent most of these two elements in the air, are variable components.   Sulfur, phosphorus, and all other elements are present in significantly lower proportions.
question: What is the most common element in the Earth's atmosphere?
answers.text: nitrogen nitrogen