What is the primary definition of "-capnia"?

The suffix "-capnia" is derived from the Greek word for carbon dioxide. It is commonly used in medical terminology to describe conditions related to the levels of carbon dioxide in the bloodstream. For example, "hypercapnia" refers to elevated levels of carbon dioxide, while "hypocapnia" refers to decreased levels. This suffix is crucial in various medical contexts, particularly in respiratory physiology and conditions affecting gas exchange in the lungs. The other options do not align with the established meaning of "-capnia" in medical terminology, as they pertain to entirely different concepts that do not relate to carbon dioxide levels.