Human Immunity and Blood

B lymphocytes secrete antibodies and cytokines and are responsible for antigen-specific humoral responses. 

These do not contain granules in them. Hence, they are placed under the category of agranulocytes.

Concave surfaces do increase the surface areas of RBCs.

It is a process in which WBCs squeeze themselves through the capillaries and reach the site of wound.

RBCs or erythrocytes help to transport oxygen to various body parts.

White blood cells are present in the blood, and they help to protect the body against infections.

Antibodies are Y-shaped proteins produced by white blood cells (specifically B cells) in response to antigens. They bind specifically to antigens and neutralize them or mark them for destruction by other immune cells. Option A is too general (blood has many components), Option B is incorrect because antibodies don't invade bacteria themselves, and Option C is wrong because RBCs don't secrete antibodies - plasma cells do.

Glycogen is NOT found in mammalian blood - it is a glucose-storage molecule stored in liver cells (hepatocytes) and muscle cells. Blood plasma contains fibrinogen (a clotting protein), adrenalin (epinephrine hormone from adrenal medulla), and various other dissolved substances, but not glycogen. When blood glucose levels drop, glycogen is broken down in the liver and released as glucose INTO the blood, but glycogen itself is never a blood component.

Anti-nuclear antibodies (ANA) have been observed in Systemic lupus erythematosus, which is an autoimmune disease.

These cells are vital parts of the cellular immune response, destroying the cells which bear any foreign antigen on their surface mainly virus-infected cells.

This immunoglobulin being an antibody plays a vital role in mucosal immunity. It is dominantly present in mucous secretions, including tears and saliva.

IgG is the most abundant form of circulating antibody.

Thrombocytes (platelets) are essential for initiating the coagulation cascade. When platelets are scarce (thrombocytopenia), blood cannot form clots properly, leading to bleeding disorders and impaired wound healing.

Acumentin is a protein found in macrophages that binds to the minus end of actin filaments.

Pus is indeed a mixture of all three components. During infection, white blood cells (leucocytes) die at the site along with dead tissue cells. Bacteria causing the infection are also present. Pus forms from this accumulation of dead leukocytes, tissue debris, bacteria, and fluid. Each component alone is incomplete.