Question

The lungs are light, spongy tissue mostly occupied by _______-filled spaces.

Option 1: Blood
Option 2: Air
Option 3: Mucus
Option 4: Lymph

Answer 1

The lungs are primarily occupied by air-filled spaces called alveoli, where gas exchange between the air and the bloodstream takes place.

Step-by-step explanation:

The lungs are mainly occupied by air-filled spaces called alveoli.

These tiny sacs are the functional units of the lungs where gas exchange between the air and the bloodstream takes place.

Each time you breathe in, the alveoli fill with air, allowing oxygen to be absorbed by the blood, while carbon dioxide is released into the air inside the alveoli and then expelled when you breathe out.