<prompt> In Corynebacterium diphtheriaDeep invasion is not seenEleks test is done for toxigenicityMetachromatic granules are seenToxigenicity is mediated by chromosomal change  <response>: Diphtheria acts by its toxin and invasion is not seen. Elekc gel precipitation test is done for determination of pathogenicity of diphtheria. Metachromatic granules are seen also called as Babes earnest granules. Bacteriophages extra-chromosomal are responsible for toxigenicity by phage conversion. 