The most active phagocytic white blood cells are neutrophils and monocytes. Neutrophil is a type of WBC (leucocyte) that has a lobed nucleus and granular cytoplasm. Neutrophils engulf bacteria and release various substance such as lysozyme and oxidizing agents. Monocyte is the largest form of WBC in vertebrates. It has a kidney shaped nucleus and is actively phagocytic, ingesting bacteria and cell’s debris.

Correct Option: D

The most active phagocytic white blood cells are neutrophils and monocytes. Neutrophil is a type of WBC (leucocyte) that has a lobed nucleus and granular cytoplasm. Neutrophils engulf bacteria and release various substance such as lysozyme and oxidizing agents. Monocyte is the largest form of WBC in vertebrates. It has a kidney shaped nucleus and is actively phagocytic, ingesting bacteria and cell’s debris.

Karl Landsteiner first reported ABO blood groups in human beings. A, B and O blood groups were discovered by Landsteiner in 1900 while AB blood group was found out by de Castello and Steini (1902). ABO blood groups are determined by the gene I (isoagglutinin). There are three alleles. I^A, I^B and I^O of this gene. Proteins produced by the I^A and I^B alleles are called A antigen and B antigen. Individuals with AB blood group have both antigen A and antigen B on their RBCs, and no antibodies for either of the antigens in their plasma.

Correct Option: A

Karl Landsteiner first reported ABO blood groups in human beings. A, B and O blood groups were discovered by Landsteiner in 1900 while AB blood group was found out by de Castello and Steini (1902). ABO blood groups are determined by the gene I (isoagglutinin). There are three alleles. I^A, I^B and I^O of this gene. Proteins produced by the I^A and I^B alleles are called A antigen and B antigen. Individuals with AB blood group have both antigen A and antigen B on their RBCs, and no antibodies for either of the antigens in their plasma.

Fibrinogen, the protein of blood plasma is converted to insoluble protein fibrin during the clotting process. The fibrinogen free fluid, obtained after removal of the clot, called blood serum, is plasma minus fibrinogen.

Correct Option: D

Fibrinogen, the protein of blood plasma is converted to insoluble protein fibrin during the clotting process. The fibrinogen free fluid, obtained after removal of the clot, called blood serum, is plasma minus fibrinogen.

Basophils secrete histamine, serotonin, heparin, etc., and are involved in inflammatory reactions.

Correct Option: B

Basophils secrete histamine, serotonin, heparin, etc., and are involved in inflammatory reactions.

Spleen is an organ of the lymphatic system located in the left side of the abdominal cavity under the diaphragm, the muscular partition between the abdomen and the chest. It is called graveyard of RBC because fragment of red blood cells, old and dead cells are constantly being removed from the blood streams by it.

Correct Option: C

Spleen is an organ of the lymphatic system located in the left side of the abdominal cavity under the diaphragm, the muscular partition between the abdomen and the chest. It is called graveyard of RBC because fragment of red blood cells, old and dead cells are constantly being removed from the blood streams by it.