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Which statement accurately describes veins?
Conduct blood at high pressures
Have valves to prevent backflow
Have a pulse
Are thick walled
The correct answer is: Have valves to prevent backflow
The statement that accurately describes veins is that they have valves to prevent backflow. Veins are responsible for returning deoxygenated blood from the tissues back to the heart, and they do this against the force of gravity, particularly in the lower extremities. To assist with this process, many veins contain one-way valves that open to allow blood to flow toward the heart and close to prevent it from flowing backward. This mechanism is crucial for maintaining proper circulation and ensuring that blood efficiently returns to the heart, especially during activities such as standing or walking. The other statements do not align with the characteristics of veins. For instance, veins typically conduct blood at lower pressures compared to arteries, as they are further away from the pumping action of the heart. Additionally, veins do not have a pulse; that characteristic is primarily associated with arteries, which experience pulsatile blood flow due to the heartbeat. Lastly, veins are not thick-walled; in fact, they have thinner walls than arteries, as they do not need to withstand high-pressure blood flow.