sentences: specialized cells are a source of chemicals that destroy disease-causing microbes
docs: listeria_monocytogenes is biochemically_harmful_substance. cytokinesis is biological_destruction. bacterial_toxin is biological_toxin. listeria_monocytogenes is bacillus_bacterium. gram_negative_cell_wall is bacterial_cell_wall. microbe is microorganism. polysaccharide_encapsulated_bacterium is bacterium. microviridae is bacteriophage_virus. biological_toxin is toxic_substance. cell_division is biological_destruction.