C3.2

2. An enzyme found in tears and saliva that digests the cell walls of bacteria.
3. A Y-shaped protein produced by lymphocytes that binds to a specific antigen.
5. Cell fragments that circulate in the blood to initiate the clotting process.
7. The ability of bacteria to survive exposure to an antibiotic through mutation.
9. Chemicals that block metabolic pathways in bacteria but do not affect viruses.
11. A long-lived lymphocyte that remains in the blood to provide rapid immunity.
12. A specific molecule on the surface of a pathogen that triggers an immune response.
14. A type of white blood cell that ingests pathogens by endocytosis.
15. A non-living pathogen that cannot be treated with antibiotics because it lacks metabolism.
16. The protein fibers that form a mesh to trap blood cells and seal a wound.
17. A weakened or killed form of a pathogen used to stimulate the production of memory cells.

1. The clumping of pathogens by antibodies to make them easier for phagocytes to find.
2. A white blood cell that produces antibodies or kills infected cells.
4. A specialized B-lymphocyte that secretes large amounts of antibodies.
6. Any living organism or virus that causes an infectious disease.
8. Selection The process where a specific lymphocyte is "chosen" to multiply and fight a pathogen.
10. The primary physical barrier that prevents the entry of pathogens into the body.
11. Membranes The internal linings that trap pathogens in sticky secretions like mucus.
13. An enzyme that converts soluble fibrinogen into insoluble fibrin during clotting.