Question

describe an activity to show that exhale air contains carbon dioxide

Answer 1

Close end of B. Breathe in. Air from atmosphere enters through A, passes through lime water and enters your mouth (cannot enter through B because closed).

Open end of B and close end of A. Breathe out. Exhaled air passes through lime water in test tube B and exits through B.

Lime water in test tube B (which contained the air you exhaled) turns milky much faster than in test tube A (which contained the air you inhaled).

Answer 2

$\textbf{Answer is in Attachment !}$