In The proportions of different gases in the atmosphere, which option helps you identify where the gas or pollutant comes from: Recall that the Earth's atmosphere contains small proportions of other gases including carbon dioxide, water vapour and noble gases?

The correct option is Nitrogen. For this source question, that option is correct because it matches Recall that the Earth's atmosphere contains small proportions of other gases including carbon dioxide, water vapour and noble gases in The proportions of different gases in the atmosphere.

Nitrogen is the correct answer for this AQA GCSE Chemistry atmosphere question. Look for the source named in the specification, not a general environmental statement. The learning objective is: Recall that the Earth's atmosphere contains small proportions of other gases including carbon dioxide, water vapour and noble gases. In The composition and evolution of the Earth's atmosphere, this means the explanation must use the subtopic The proportions of different gases in the atmosphere and avoid drifting into a different gas, pollutant, climate, or early-atmosphere idea. Checkpoint 18: this page uses the source angle so students can practise one distinct reasoning route before moving to the next question.