Final answer:
Dyspnea, or shortness of breath, can be caused by pneumonia, emphysema, and COPD. Pneumonia is an infection or injury of the lungs, emphysema is a lung disease caused by smoking, and COPD is a chronic lung disease with poor airflow.
Step-by-step explanation:
Dyspnea, also known as shortness of breath, can have various causes. Some of the most common causes of dyspnea include pneumonia, emphysema, and chronic obstructive pulmonary disease (COPD). Pneumonia is an infection or injury of the lungs that can cause fluid buildup and difficulty breathing. Emphysema is a lung disease often caused by smoking, where the walls of the alveoli break down, leading to shortness of breath. COPD is a chronic lung disease characterized by poor airflow, resulting in shortness of breath and a cough.