Practice question

Correct option is B, High CO2 in blood. In Lung Volumes, Capacities and Regulation, the accurate description is High CO2 in blood, and that is what you should commit to memory. Keep the definition tight and the role clear — this is mainly a definition check, and High CO2 in blood is the standard term or meaning used in Lung Volumes, Capacities and Regulation. Then High CO2 in blood is the answer you can defend. Check yourself by covering the options and writing the answer first, then matching the letter — that builds confidence. If the wording feels dense, translate it into everyday language first, then map that plain sentence back onto High CO2 in blood.