issb general knowledge MCQ #788

Which gas do humans exhale most?

issb general knowledge MCQ #788

  1. Question 1

    Q1. Which gas do humans exhale most?

    • A) Oxygen
    • B) Carbon dioxide
    • C) Nitrogen
    • D) Hydrogen

    Answer: Carbon dioxide

    Explanation: Humans exhale carbon dioxide as a waste product of respiration. Work each step carefully; ISSB math rewards accuracy under time pressure.