Question

circulatory structures that return blood to the heart are called:
○ capillaries.
○ arteries.
○ muscles.
○ veins.

Explanation:

To solve this, we analyze each option:

• Capillaries: Facilitate exchange between blood and tissues, not main return to heart.
• Arteries: Carry blood away from the heart.
• Muscles: Not part of the circulatory system's blood - return structures.
• Veins: The circulatory structures responsible for returning blood to the heart.

Answer:

D. Veins