What do the terms ...

antigen

antibody

white blood cell

specific

pathogen

... mean?

Antigen: is a a foreign substance or toxin that causes a immune response.

Antibody: it is a blood protein that is produced in response to an antigen.

White blood cell: also called a leukocyte and is a cell that counteracts against antigens.

Specific: If your're talking about the biology definition then it is, of or pertaining to a species.

Pathogen: a virus or bacteria that can cause a disease.