The correct answer is: Veins have fewer internal valves than do lymphatic vessels.
Some of the differences between blood (veins) and lymphatic vessels are:
• Valves of lymph vessels are more closely spaced than those of veins
• Blood vessels are not interrupted (closed circulatory system) while lymphatic vessels are interrupted via lymphatic nodes.
• Veins are connected with the central pump of the circulatory system-heart, while lymphatic vessels don’t have such structure.
