What is the process of directly injecting pre-formed antibodies into the body called?

Identify the receptors present on $T_{H}$ cells and $T_{C}$ cells,respectively.

Lymphoid tissue is found in:

All of the following are examples of mucosa-associated lymphoid tissue $(MALT)$ except:

Assertion: Interferons are effective against viruses.
Reason: Proteins which can be synthesized only by genetic engineering are effective against viruses.

Which of the following statements are correct regarding the structure and types of antibodies in humans?
$i$. Antibodies are also called Immunoglobulins that are produced as an immune response to antigenic stimulation.
$ii$. They are produced by all types of $T$-lymphocytes and $B$-lymphocytes.
$iii$. An antibody is a $Y$-shaped molecule formed of four polypeptide chains. Antibodies present in plasma determine many blood group systems like $ABO$,$Rh$,$P$,$MNS$ etc.
$iv$. An antibody molecule consists of two antigen-binding sites called paratopes.