Fill in the Blank QuestionFill in the blank question.Humans have a circulatory system, as blood is always moving through blood vessels and the heart.

Humans have a closed circulatory system, as blood is always moving through blood vessels and the heart.

In a closed circulatory system, the blood is contained within a network of blood vessels and is pumped by the heart throughout the body. This system allows for efficient transportation of nutrients, oxygen, and waste products. The constant movement of blood ensures that all cells receive the necessary materials for metabolic processes while facilitating the removal of carbon dioxide and other metabolic wastes. This setup is crucial for maintaining homeostasis and responding to the body's varying demands for oxygen and nutrients, especially during physical activity or stress.