Human Immunity and Blood

Blood group AB individuals have both A and B antigens on their RBCs, so they don't produce anti-A or anti-B antibodies. This makes them universal recipients. Option A correctly states this, though they can receive from A, B, AB, and O donors, not just A and B.

AB blood group is called the universal recipient because individuals with AB type have both A and B antigens on their red blood cells and no anti-A or anti-B antibodies in their plasma. This allows them to receive blood from any group (A, B, AB, or O) without adverse reactions. O+ is the universal donor for positive blood types only.

The Bombay Blood Group (hh phenotype) is the rarest blood type in the world, occurring in approximately 1 in 10,000 people in India and 1 in 1,000,000 globally. It lacks H antigens and can cause severe transfusion reactions if mismatched with ABO types.

Red blood cells (erythrocytes) are produced in the bone marrow through hematopoiesis. In adults, this primarily occurs in the flat bones (sternum, ribs, pelvis). The liver produces RBCs in fetuses, and kidneys produce erythropoietin that stimulates RBC production, but don't make the cells themselves.

Blood group O individuals can only receive from O group because they have both anti-A and anti-B antibodies. They are universal donors but can only accept from their own type.

While Type O is indeed the most common blood type globally, the existence of 'Type A-H' as a legitimate blood type is questionable. The standard ABO system includes A, B, AB, and O - not A-H.

AB positive blood group individuals are universal recipients - they can receive blood from any blood group (A, B, AB, or O) because they have both A and B antigens and no anti-A or anti-B antibodies in their plasma.

Leukemia is a cancer of the body's blood-forming tissues, including the bone marrow and the lymphatic system. It involves abnormal production of white blood cells, making it fundamentally a blood disease.

Red blood cells (erythrocytes) are produced in the bone marrow through erythropoiesis, primarily in the flat bones like sternum, pelvis, ribs, and vertebrae. The liver, kidneys, and heart have other essential functions but don't produce RBCs.

O+ blood can be donated to any Rh-positive recipient (A+, B+, AB+, O+) because it lacks A and B antigens but has the Rh factor. It cannot be given to Rh-negative recipients as they would react to the Rh protein. The Rh+ factor means O+ can only go to other positive blood types.

Urticaria is the medical term for hives - itchy, raised welts on the skin that result from allergic reactions or other triggers. Options A and B refer to other skin conditions (atopic dermatitis and eczema are related but different), while folliculitis is a hair follicle infection.