Emphysema is a form of chronic obstructive pulmonary disease (COPD). A person who has emphysema finds breathing out difficult. Why does emphysema make breathing out difficult?
- ASmooth muscle fibres in the airways are destroyed.
- BToo little mucus is produced in the bronchi.
- CThe elasticity of the alveoli decreases.
- DThe surface area of the alveoli becomes larger.