Four important of Residual air.

Explanation:

The residual volume function to keep the alvedi open even after maximum expiration. In healthy, lungs, the air that makes up the residual volume allows for contionual gas exchange to occur between breaths.

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).

one centimetre is equal to 0.01 metres