What is the adaptations of vein in live animal?

Veins in live animals are adapted to efficiently return deoxygenated blood to the heart. They have thinner walls compared to arteries, allowing them to be more flexible and accommodate varying blood volumes. Additionally, many veins contain one-way valves that prevent backflow, ensuring unidirectional blood flow despite lower pressure. The presence of surrounding skeletal muscles also aids in venous return through contraction and relaxation during movement.