Statement 1: A complex of blood vessels beginning and ending in capillaries through which blood circulates before returning to the heart is called a portal system.
Statement 2: All mammals have a hepatic portal system.
Both A and R is false.
A portal system is a complex of blood vessels which begin and end in capillaries. A portal vein collects blood from a particular organ and distributes the blood to some other organ instead of sending it directly to the heart. All mammals have a hepatic portal system which carries blood from the digestive tract to the liver for various metabolic activities. Therefore, both A and R are true.