Answer:
The vasa vasorum, the collection of small arteries and veins supplying blood to the smooth muscle and fibroblasts within blood vessels, is found in the tunica externa.
Step-by-step explanation:
In order to understand the answer above let explain the concept of tunica externa
This in Latin means outer coat and can also be called 'tunica adventitia' which also means "additional coat in Lain",it is the outermost layer of the a blood vessel covering the tunica media(This is a Latin word translated as middle coat in English which is the middle layer of an artery or a vein it lies between the tunica externa and the tunica initima which is the innermost part of the artery or vein).
An Artery
We can define an artery as a blood vessel that transports blood from the heart to other parts of the body.
An Vein
We can define a vein as a blood vessel that transports blood to the heart
and we can define blood vessel as a tube that carries blood in the circulatory system.