What do antibodies fight against?

Where are $B$-cells and $T$-cells formed? How do they differ from each other?

What is the immune response called when our body encounters a pathogen for the first time?

Which of the following immunoglobulins constitutes the largest percentage in human milk?

What are antigens composed of?

Choose the true statements.
$I.$ Innate immunity is accomplished by providing different types of barriers.
$II.$ Acquired immunity is present from birth and is inherited from parents.
$III.$ Sweat,tears,acid in the stomach,and saliva prevent microbial growth.