What does $Rauwolfia$ $vomitoria$ produce?

Give the scientific names of any two microorganisms inhabiting the human intestine.

Which one of the following organisms is used as an indicator of water quality?

Fleming,Chain,and Florey were awarded the Nobel Prize for their work on antibiotics in ...........

Identify the correct statements from the following:
$(A)$ Microbes have been used for centuries.
$(B)$ Not all microbes are pathogenic.
$(C)$ There are various methods to culture microbes in a nutrient medium.
$(D)$ Fungi,Cycas,viruses,and bacteria are examples of microbes.