Question

What is the likely source (reservoir) of organisms that grew at 35 degrees C, and how do they survive at room temperature without nutrients?

Answer 1

It is necessary to incubate the plate at two different temperatures because some organisms can grow fastly at room temperature and some grows at body temperature that is 37 degree Celsius. So the source of microorganisms at 35 degree Celsius is human body. They survive because microbes are inert and nutrients present which are not seen to our eyes. Bacteria have spores as a stage of their life cycle. Spores can survive without water or nutrients for long time that may be some of them for centuries. Viruses can survive for long time untill and unless they infect a host cell.

When these organisms change their state end transfer to suspended state. At this stage they are not alive but in the biological state they resume their life as nutrients and water.