a) lipopolysaccharides or endotoxins, derived from the cell walls of gram-negative pathogenic microorganisms, are toxic to human tissue and cause inflammation and destruction of the periodontal attachment. b) endotoxins are embedded in the cemental surface and in the superficial biofilm and cannot be removed readily. group of answer choices statement a is true and statement b is false. statement a is false and statement b is true. both statements are true. both statements are false.