What is the adaptation of the veins to surve their function?

Veins have several adaptations that facilitate their function in returning deoxygenated blood to the heart. They have thinner walls than arteries, allowing them to be more flexible and accommodate varying blood volumes. Additionally, they possess one-way valves that prevent backflow, ensuring efficient blood flow towards the heart. The surrounding skeletal muscles also help pump blood through veins during movement, enhancing circulation.