Question

Which of the following is not a component of immune system?

Options

• Lymphocytes

• Plasma Proteins

• Red Blood Cells

• Bone Marrow

Answer 1

Red Blood Cells

Explanation:

Red blood cells (erythrocytes) transport oxygen and do not participate in immune responses, so they are not considered components of the immune system. Lymphocytes are primary immune cells, plasma proteins include immune effectors (e.g., antibodies, complement, interferons), and bone marrow is a primary lymphoid organ where immune cells are formed.