Question

a ____ is one which starts in capillaries and end in capillaries

Answer 1

Capillaries are the site of internal or cellular respiration and is responsible for the utilization of oxygen by the tissue and the transporting of carbon dioxide as waste for elimination by the lungs.Hence the arterial blood system branches extensively to deliver blood to over a billion capillaries in the body. A portal vein is one which start with capillaries and also ends in capillaries. 

Answer 2

Heya!!
Your answer is portal veins.



Hope it helps you.
P