circulatory system
The circulatory system contains your heart your blood cells and your veins
BLOOD-blood contains cells
The fluid that leaves blood cells is plasma, which is a yellowish component of blood that contains water, electrolytes, hormones, and proteins. The small particles it contains are platelets, which help in blood clotting, and white blood cells, which are part of the immune system and help fight infections.
The circulation system in the body contains hemoglobin, more specifically the blood.
White blood cells
The yellow tissue in the center of the bones produces white blood cells.
Blood contains four things: white blood cells, red blood cells, platelets and plasma.
Because it also contains red blood cells
Respiratory system
it contains oxygen so you can breathe and it contains blood cells
I think you mean served? The blood transports oxygen (as oxyhaemoglobin) to the cells of the body, it contains the cells that are a part of our immune system (white blood cells). It transports away from cells CO2 and urea, and it carries chemical signals such as hormones. That's the potted version - try Wikipedia for more.
The circulatory system is used to transport blood throughout the body. More specifically, blood contains several specific types of cells: platelets, red blood cells, white blood cells, and nutrients. Platelets block up external wounds to prevent bleeding. Red blood cells transfer nutrients throughout the body, and white blood cells protect the body from external germs, such as disease.