Which of the following is true about veins?

Question

Which of the following is true about veins?

Quizplus · Accepted Answer

Due to the lower pressure in the venous system and the fact that most blood is trying to return back to the heart against the force of gravity, veins have valves that prevent blood from moving backwards.
Veins do not contain thick muscular, walls like arteries do. If venous walls were thick like arterial walls, there would be more resistance for blood flowing into veins. Since blood in the venous side is already under a lower pressure, this would create a problem for blood to return to the heart.
Venous blood carries oxygen deficient blood back to the heart, not away from it.
You may use the diagram below as a visual reference for the structure of the vein.
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Which of the Following Is True About Veins