<prompt> Which of the following is a bacteria taxonomically -ChlamydiaRickettsiaMycoplasmaAll  <response>: Ans. is a i.e., Chlamydia; b i.e., Rickettsia; c i.e., Mycoplasma Bacteria . Bacteria are single celled microorganisms which can exist either as independent free living organisms or as parasites dependent on other organisms for life. . There are typically 40 million bacterial cells in a gram of soil and 1 million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion 5 X IV bacteria on eah. 