Also known as the circulatory system, this body system controls the body's steady circulation through the heart and blood vessels.

Also known as the circulatory system, this body system controls the body's steady circulation through the heart and blood vessels.

• A. Muscular System
• B. Melanin
• C. Hair Follicle
• D. Circulatory System

Answer: (D)

The body system that keeps blood moving continuously through the heart and vessels, delivering oxygen and nutrients while removing wastes, is the circulatory system (also called the cardiovascular system). The heart acts as a pump, pushing blood through arteries, capillaries, and veins to reach every part of the body and then loop back. This ongoing flow is what maintains steady circulation. The other options don’t describe circulation: the muscular system governs movement and posture; melanin is the pigment that gives skin and hair their color; a hair follicle is the structure that produces hair.

The body system that keeps blood moving continuously through the heart and vessels, delivering oxygen and nutrients while removing wastes, is the circulatory system (also called the cardiovascular system). The heart acts as a pump, pushing blood through arteries, capillaries, and veins to reach every part of the body and then loop back. This ongoing flow is what maintains steady circulation.

The other options don’t describe circulation: the muscular system governs movement and posture; melanin is the pigment that gives skin and hair their color; a hair follicle is the structure that produces hair.