I believe the answer to this question is a food web.
Food Web definition: "<span>a series of organisms related by predator-prey and consumer-resource interactions; the entirety of interrelated food chains in an ecological community."
Source: </span>http://www.dictionary.com/browse/food-web
Answer:
1. Circulatory System
2. White Blood Cells
3. Capillaries
4. Vein
5. Carbon Dioxide (CO²)
6. Circulatory System
7. Immune System , Fights
8. Red Blood Cells
9. Gas Exchange
10. Transport
11. Lungs
12. Artery, Heart and Lungs
13. Heart
14. Important Plant
15. Alveoli
