Which type of blood vessel typically lacks one or more of the three tunics?

Answer;

Terminal capillaries lacks the three layers.

Explanation;

-All arteries and veins contain three layers, namely; the tunica intima, tunica media and the tunica adventitia. However, Terminal capillaries lacks the three layers, because they are only one cell layer thick, they instead have only tunica intima.

-Tunica intima is the innermost layer of endothelium and associated connective tissue. The middle layer is the tunica media and it is made of smooth muscle cells. It extends from the internal elastic lamina to the external elastic lamina and it varies the most of the three tunics and is diagnostic for classifying vessels.

-The last layer is the tunica adventitia with the outermost collagen rich connective tissue layer that blends with the loose connective tissue of surrounding organs helping to attach the vessels to surrounding tissue.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.