In the space provided, give me the word(s) that most adequately complete each sentence.

A) Traditionally, the most important reference book for microbial diversity and characteristics has been the __________________________.

B) Bacteria from the genera Rickettsia and ______________ are unusual in that they are obligate intracellular parasites

C) Mycobacteria differ from other bacteria in that they contain _________________ in their cell walls.

D) Bacteria from the phylum _______________________ are important in ruminant health, in that they secrete cellulase to help with digestion.