the circulatory system is responsible for transporting oxygen and nutrients throughout the bloodstream the circulatory system is what level

Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood.

Explanation: A protein called hemoglobin in the red blood cells then carries the oxygen around your body.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.