Enumerated powers. The enumerated powers are a list of items found in Article I, Section 8 of the U.S. Constitution that set forth the authority of Congress. In summary, Congress may exercise the powers that the Constitution grants it, subject to the individual rights listed in the Bill of Rights.
The average adult has 10-12 pints of blood. Someone needs blood every two seconds in the U.S. 40,000 pints: Amount of donated blood used each day in the U.S. and Canada. Through a process of separating blood into its individual parts, a single unit of blood can help extend the lives of as many as three people.
The amount of blood in the human body depends on size (body mass is more important than height). An average man of 150 lbs or 70 kgs will have around 8 pints or 5.2 litres of blood. A woman of 110 lbs (50 kgs) will have about 3.3 litres of blood ; about 5 pints.