U.S. Army Lt. Col. John Kallo, the deputy chief of staff for the 1st Cavalry Division, watches a movie while donating plasma during the blood drive in the Robertson Blood Center at Fort Hood, Texas, Nov. 4, 2013. Plasma is the component in blood that adds volume to it. Soldiers who donate plasma and or platelets can donate every two weeks whereas Soldiers who give blood have to wait 56 days.