The injection of serum from a horse,which has been repeatedly injected with cobra venom,into a person bitten by a cobra results in:

The antibodies are produced by the

Read the given statements carefully and identify the incorrect statements.
$(1)$ In active acquired immunity,antibodies are directly injected into the body.
$(2)$ Vaccination is considered under passive acquired immunity.
$(3)$ The human body distinguishes between self and non-self with the help of $Tc$ cells.
$(4)$ Innate immunity consists of four types of barriers.

Memory cells ............

Identify the odd one out from the following.

Interferons are ...........