ahhh yes the simple question now i learned this when i was a little lad, you see there are many foreign substances, two ducts, tissue fluid, lymph, white blood cells, lymph veins, protect body, bloodstream, lymphocytes, lymph capillaries.so that means many foreign substances, two ducts, tissue fluid, lymph, white blood cells, lymph veins, protect body, bloodstream, lymphocytes, lymph capillaries.so that means many foreign substances, two ducts, tissue fluid, lymph, white blood cells, lymph veins, protect body, bloodstream, lymphocytes, lymph capillaries.so that means many foreign substances, two ducts, tissue fluid, lymph, white blood cells, lymph veins, protect body, bloodstream, lymphocytes, lymph capillaries.so that means that there is a spsific sample. YOUR WELCOME BRO! THIS WILL HELP YOU JUST READ ALL OF IT.