Arteries and veins are BLOOD VESSELS
Blood cannot be a tissue, though it may have RBCs or WBCs, collection if cells as you say.. they don't really "join up" to do specific tasks. Let's just say the blood is a mixture of cells, ions etc. etc.
You seem right VIN but we had that dumb question in our mocks. It was from GCE and it called blood to be a tissue I think. Not really sure of the year. Anyway, screw it. GCE doesn't count
. But about an artery, isn't it a tissue?? Cause I came across a question in MJ 00 that called it an organ. (the mark scheme for those years is just downright nuts...). Just 3 pm tomorrow and after that no force other then that of God can force me to study for at least 6 weeks. Fifa 2010 here I come!!!!!