Sources
![Picture](/uploads/6/4/8/8/6488017/8539950.png?258)
http://www.nobelprize.org/educational/medicine/landsteiner/readmore.html
http://www.news-medical.net/health/What-is-a-Macrophage.aspx
http://www.webmd.com/a-to-z-guides/blood-transfusion-overview
http://www.sciencedaily.com/articles/n/natural_killer_cell.htm
http://www.biologyguide.net/diseases/immune_system.htm
http://www.thebody.com/content/art1788.html
Unit 3 Biology Note Book - Pages 79, 80, 84
http://www.news-medical.net/health/What-is-a-Macrophage.aspx
http://www.webmd.com/a-to-z-guides/blood-transfusion-overview
http://www.sciencedaily.com/articles/n/natural_killer_cell.htm
http://www.biologyguide.net/diseases/immune_system.htm
http://www.thebody.com/content/art1788.html
Unit 3 Biology Note Book - Pages 79, 80, 84