<span>George Simmel was a pioneer in sociological studies due to the fact that he developed the concept of the sociological imagination, and believed that societies can be understood through an empirical scientific approach known as positivism which is still used in research today.</span>
Valves ensure blood flows toward your heart. Vein valves work to bring the blood that flowed down via arteries back up to your heart.
Providing long-term control over the body's internal conditions
Keeping conditions within a normal range
Adjusting the "set point" for body temperature based upon level of activity
