What is produced in the host body when the host is exposed to antigens?

Which antibody is present in the highest concentration in mother's milk?

Identify the barrier of innate immunity in which virus-infected cells secrete proteins called interferons.

Identify the statement that is $\text{NOT}$ correct.

When a pathogen (antigen) enters the body for the second time,which type of antibody is produced in the secondary immune response?

Given below are two statements:
Statement $I$: Bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced.
Statement $II$: Both bone marrow and thymus provide micro-environments for the development and maturation of $T$-lymphocytes.
In the light of the above statements,choose the most appropriate answer from the options given below: