Muscle weakness is a symptom of a wide variety of mild to serious diseases, disorders and conditions. Muscle weakness can result from infection, trauma, malignancy, autoimmune diseases, and other abnormal processes.
Difference between O+ and O- Blood Group. Key difference: The blood groups O+ and O- are universal donors. The only difference is in the recipients to whom the blood is transfused; O+ can be transfused to any positive blood groups, whereas O- is transfused to both positive as well as negative blood groups. O+ blood group is a common blood group among most of the people.
O-negative blood group has also been associated with certain personality traits. Blood group is determined by the presence of antigen(s) on the membrane of red blood cells. The antigens are special molecules that can elicit an immune response.-negative blood group is the  universal donor  blood group. This means that a person with any blood group can receive O-negative blood. This is very important in emergency situations when a person requires immediate blood transfusion and there is no time to test his/her blood group.