Which of the following distinguishes lymphatic vessels from veins?
-lymphatics transport fluids toward the heart
-lymphatics lack the three tunics present in veins
-lymphatics have valves, while veins do not.
-permeability of the walls

The correct answer is: Permeability of the walls

The walls of lymphatic vessels, capillaries are more permeable than those of blood capillaries and because of that able to absorb larger particles from the tissues, such as proteins, cells, bacteria.

Some of the differences between blood and lymphatic vessels also are:

•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.