Which of the following is a bacteria taxonomically -

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.