Final answer:
The combining form 'circulat/o-' in circulation denotes the act or function related to the movement of blood or another substance through a closed circulatory system, like systemic circulation in humans.
Step-by-step explanation:
The combining form circulat/o-, as seen in circulation, means pertaining to circulation or the act or process of moving blood through the vessels of the body or another substance through a closed system. For instance, systemic circulation is the part of the cardiovascular system that carries blood between the heart and the body. This type of circulation is imperative for delivering oxygen and nutrients to tissues and removing waste products.
Moreover, a closed circulatory system is where the blood is kept separate from the extracellular fluid and contained within vessels, which is typical in humans and other vertebrates. In systemic circulation, blood flows away from the heart to the brain, liver, kidneys, stomach, and other organs, limbs, and body muscles, then returns to the heart. This system works in tandem with pulmonary circulation, which is the circuit through which blood is sent to the lungs to acquire oxygen.