Final answer:
The physiologist's examination of blood components in a diabetic patient is related to the field of analytical chemistry, which involves identifying and quantifying chemical substances in samples. So the correct answer is option D.
Step-by-step explanation:
When a physiologist examines the composition and quantity of each component in a blood sample from a diabetic patient, this study falls under the field of analytical chemistry. Analytical chemistry is focused on determining the composition of matter by separating, identifying, and quantifying chemicals in samples. Techniques like blood glucose level measurement, hemoglobin analysis, and the A1C test, which measures average blood glucose levels over a period, are examples of analytical methods used to diagnose and manage conditions like diabetes mellitus. These procedures often involve the use of sophisticated instruments and methodologies that are within the purview of analytical chemists.