when considering the anatomic structure of arteries, capillaries and veins, which cell layer is common to all blood vessels regardless of their size

Tunica

Explanation:

The cell layer which is common to all blood vessels regardless of their size is known as Tunica. These layers usually lines the layers of the connective tissues of the body such as the artery, vein and capillary.

The Tunica is divided into three parts known as Tunica intima, Tunica media and Tunica adventitia. They usually vary in size according to the blood vessels I’m which they are found in which depicts different and specialized function.

a symbiotic relationship with the mitochondria