That means that the vans are very busy indeed, all the time. So it's a good job we've got the circulatory system to transport nutrients, water and oxygen to the entire body. Inside you ...

That means that the vans are very busy indeed, all the time. So it's a good job we've got the circulatory system to transport nutrients, water and oxygen to the entire body. Your circulatory ...

Circulatory system: Blood vessels Laid end-to-end, an adult's arteries, veins and capillaries would stretch for about 100,000 miles - enough to wrap around the world nearly four times.