Discuss the roles that blood performs.
You may choose to discuss how the blood i

Discuss the roles that blood performs.
You may choose to discuss how the blood interacts with the digestive or respiratory or
urinary systems. You should introduce all the functions of blood and then probably narrow
your focus to one or two. You could discuss the role of capillaries. You might wish to include
a discussion of the cells found in blood and what they do. 
This paper should include 7 sources from journals and textbooks or 
academic sources