Which suffix means "carbon dioxide"?

The suffix "-capnia" is derived from the Greek word "kapnos," which means smoke or vapor but is often used in medical terminology to refer specifically to the presence of carbon dioxide in the blood. In medical contexts, "-capnia" is often paired with other prefix elements to articulate various conditions related to carbon dioxide levels, such as hypercapnia (elevated carbon dioxide in the blood) and hypocapnia (reduced carbon dioxide levels).

The other suffixes listed do not have a direct relationship with carbon dioxide. For example, "-cardia" refers to the heart or heartbeat, "-cele" indicates a hernia or swelling, and "-crit" pertains to the ratio of blood cells to plasma in a sample. Understanding the meanings of these suffixes helps clarify why "-capnia" specifically denotes carbon dioxide, making it the correct choice in this context.