Relating to blood or the study of blood and blood-forming organs.

• A. Hematology
• B. Circulatory
• C. Immunology
• D. Hematologic

Answer: (D)

The idea being tested is the distinction between a term that describes something related to blood and the term for the field that studies blood. Hematologic describes something related to blood, the blood-forming organs, or blood conditions. That makes it the best fit for the phrase “relating to blood or the study of blood and blood-forming organs” because it conveys the descriptive sense (relating to blood) directly.

Hematology, on the other hand, is the field of study—the science of blood and its diseases. So it’s the noun form referring to the discipline rather than the attribute.

The other options don’t fit the meaning as neatly. Circulatory pertains to the system that moves blood around the body, not to blood itself or its formation. Immunology deals with the immune system, not blood specifically. Hematologic is the adjective form describing something related to blood, which is exactly what the prompt is asking for.