Questions: Which of the following distinguishes lymphatic vessels from veins? lymphatic vessels transport fluids toward the heart. lymphatic vessels collect larger materials lymphatic vessels lack the three tunics present in veins. lymphatic vessels have values, while veins do not.

Solution Steps

The question asks what distinguishes lymphatic vessels from veins. Let's examine each option:

• Lymphatic vessels transport fluids toward the heart: Both lymphatic vessels and veins carry fluids towards the heart.
• Lymphatic vessels collect larger materials: While lymphatic vessels _can_ collect larger materials than blood capillaries, this is not a distinguishing feature between lymphatic vessels and _veins_.
• Lymphatic vessels lack the three tunics present in veins: This statement is true. Veins have three tunics (intima, media, and externa), while lymphatic vessels have thinner walls and fewer smooth muscle cells in their tunica media.
• Lymphatic vessels have valves, while veins do not: This statement is false. Veins also have valves to prevent backflow.

The only option that correctly distinguishes lymphatic vessels from veins is the absence of the three well-defined tunics present in veins.

Final Answer: The correct answer is: lymphatic vessels lack the three tunics present in veins.