which of these conditions commonly follows another illness?\n\n- bronchitis\n- the common cold\n- asthma\n…

Brief Explanations:

Pneumonia is a respiratory infection that often occurs as a secondary complication following a primary viral illness, such as the influenza (flu) or the common cold. While the initial illness weakens the immune system and damages the respiratory tract's defenses, bacteria or viruses can more easily invade the lungs, leading to the inflammation and fluid buildup characteristic of pneumonia. In contrast, conditions like asthma and cystic fibrosis are chronic genetic or long-term inflammatory disorders, and the common cold is typically a primary infection itself.

Answer:

pneumonia