True/False: Mark the following statements as true (T) or false (F). If the statement is false, correct it to make it a true statement. ____ a. The three major circuits of blood flow in the body are the systemic, coronary, and pulmonary circuits. ____ b. The femoral vein is a superficial leg vein that drains the medial leg and thigh. ____ c. The external jugular veins drain blood from the brain. ____ d. Most everything we ingest must pass through the hepatic portal system before entering the systemic circulation..