Question

Which of the following blood groups is called a universal blood donor?
A.O Rh+ve
B.O Rh-ve
C.AB Rh+ve
D.AB Rh-ve

Answer 1

The bodily fluid present in humans and animals which is responsible for delivering necessary substances such as oxygen and nutrients to the cells and carrying away metabolic waste products from these cells is known as blood.

Complete answer:
Blood plasma in vertebrates consists of blood cells, proteins, hormones, glucose, carbon dioxide, and glucose and they make up to 55 percent of the blood fluid. The main protein present in the blood plasma is Albumin. The blood performs various functions which include transport of oxygenated blood and nutrients such as dissolved fatty acids, amino acids, and glucose to the tissues, removal of waste metabolites such as urea, lactic acid, and carbon dioxide. They also assist in the regulation of the core body temperature, transporting hormones and damaged tissue signals, coagulation, and circulation of white blood cells which facilitate the immunological response of the body. Blood cells are of different types namely, White blood cells (also known as leukocytes), red blood cells (also called erythrocytes), and platelets (thrombocytes). Red blood cells are found to be in abundance in the human blood plasma. They comprise an iron-containing protein called the hemoglobin which facilitates the transport of oxygen. The blood appears to be bright red when the hemoglobin is oxygenated and deep red when the hemoglobin is deoxygenated.
Blood is classified based on the presence and absence of antibodies and antigens present on the red blood cell surface. Blood groups are of four types A, B, AB, or O, which are either Rh (rhesus)-negative or Rh (rhesus)-positive. Blood type information is necessary during a blood transfusion. Most of the blood types are a combination of blood types inherited from both parents. Depending on the blood group system the antigens may be either carbohydrates, glycolipids, proteins, or glycoproteins. The blood group system which consists of two antigen, i.e. antigen A and B, and two antibodies, i.e. antibody A and B is known as the ABO blood group system. The antibodies are present in the serum whereas the antigens are present on the red blood cells. The four blood types are distinguished based on the type of antigen and antibody present in them. For instance, blood type ‘A’ consists of the antigen A and antibody A, the blood type ‘B’ has the antigen B and antibody A in them, the blood type that has both A and B antigens in them is ‘AB’ but they lack antibodies and blood type ‘O’ has neither antigen A nor B but has antibody A and B in them. Because of this reason, anyone with the blood group can only receive blood transfusions only from individuals with blood group O, but they can donate blood to individuals of any blood type, i.e. A, B, O, or AB. Mostly blood group O Rh-negative is considered as the universal donor as they are compatible with any blood group. Due to the overuse of this blood type for transfusion, the American Association of Blood Banks and the British Chief Medical Officer's National Blood Transfusion Committee have issued a statement restricting the usage of this blood type to pregnant women, emergency blood transfusion and to an individual with O Rh-negative blood type.
Therefore, the correct option is B. O Rh-negative.

Note: The International Society of Blood Transfusion (ISBT) recognizes a total of 38 human blood group systems as of 2019. Karl Landsteiner discovered the ABO blood group system in 1900. In the year 1907, Jan Janský was credited for the first classification of the four blood types which remain in use today. In 1937, the Rhesus factor was discovered.