Final answer:
Pneumonia, a condition where alveoli fill with fluid, can occur in either the right or left lung. Free air in the lung, indicating a pneumothorax, is also a condition that can affect either lung.
Step-by-step explanation:
The two possible conditions mentioned in the statement are related to pulmonary issues. When alveoli become inflamed and fill with fluid, it indicates pneumonia, which can occur in either lung. The option of fluid in the right lung or fluid in the left lung would both be applicable.
Additionally, the occurrence of free air in the lung refers to a condition known as a pneumothorax, which is not explicitly mentioned in the diseases list provided but also can occur in either lung. Therefore, the options free air in the left lung or free air in the right lung are both potential conditions.