I think it’s B I’m not sure
Meteorology because it is a metaphoric rocks
I think it would be Ionic Solution
The total volume of the gas-exchanging region in the lung is called alveolar volume.
The alveolus is an air sack-like organ in the end of the respiratory airway. The alveolus is the site where gas-exchanging happens, so only air inside alveolus that will undergo actual exchange. Air in bronchus or trachea wouldn't do exchange