Practice MCQ Questions and answers on Biology-GK

They protect you against illness and disease. Think of white blood cells as your immunity cells. In a sense, they are always at war. They flow through your bloodstream to fight viruses, bacteria, and other foreign invaders that threaten your health.

The average Life span of RBC is 120 days.

Red blood cell, also called erythrocyte, cellular component of blood, millions of which in the circulation of vertebrates give the blood its characteristic colour and carry oxygen from the lungs to the tissues.

Blood group O – has no antigens, but both anti-A and anti-B antibodies in the plasma. blood group AB – has both A and B antigens, but no antibodies.

Normal blood pressure: 90/60 to under 120/80 mm Hg in human beings.

The main job of red blood cells, or erythrocytes, is to carry oxygen from the lungs to the body tissues and carbon dioxide as a waste product, away from the tissues and back to the lungs. Hemoglobin (Hgb) is an important protein in the red blood cells that carries oxygen from the lungs to all parts of our body.

Lymphocytes develop in the thymus and bone marrow (yellow), which are therefore called central (or primary) lymphoid organs.

Capillaries are tiny blood vessels connecting arteries to veins. These blood vessels carry oxygen and nutrients to individual cells. Capillaries are the smallest blood vessels in the body, and have walls only one or two cells thick.

The red blood corpuscles or erythrocytes usually carry antigens and there are two types of antigens. The A group persons have antigen A in their red corpuscles and the B group have antigen B in their red corpuscles. The AB group person have both antigen A and antigen B in their erythrocytes. The 'O' group persons have no antigens in their red corpuscles.

AB+ is universal acceptor.