Which of the following refers to the study of a subject in medical terminology?

The suffix that refers to the study of a subject in medical terminology is -logy. This suffix originates from the Greek word "logos," which means "study" or "discourse." In medical terminology, it is commonly used to denote a field of study or practice, such as biology (the study of life), cardiology (the study of the heart), or dermatology (the study of the skin). Therefore, when applied in a medical context, -logy indicates an area of knowledge or expertise concerning specific body systems, diseases, or general health concepts.

The other suffixes provided do not pertain to the study of subjects. For instance, -rrhea refers to a flow or discharge, commonly used in contexts like diarrhea or rhinorrhea (nasal discharge). -emia signifies a condition of the blood, as in anemia (a deficiency of red blood cells) or hyperglycemia (high blood sugar levels). Lastly, -megaly denotes enlargement, as in cardiomegaly (enlargement of the heart) or splenomegaly (enlargement of the spleen). Each of these terms describes specific conditions or phenomena rather than a field of study. Thus, -logy is the appropriate choice for