Answer
Developmentally, embryonic lymphatic vessels are most closely associated with the:
a. veins
Work Step by Step
As lymphatic vessels increase in size, their layers more closely resemble those of veins, and like veins, they contain valves to help prevent fluid backflow. Valves of lymph vessels are more closely spaced than those of veins, and the vessels may have a beaded appearance with the bulging of fluid between the valves.