Are veins the blood vessels that carry from all parts of body back to heart?

Veins are indeed the blood vessels that bring deoxygenated blood back from all parts of the body to the heart. Oxygen-rich blood, on the other hand, is carried by arteries from the heart to the body's tissues. This constant flow of oxygenated and deoxygenated blood through the network of blood vessels is essential for the proper functioning of the body.