Question

what are the benificial and harmful aspects of microorganisms

Answer 1

Microorganisms are beneficial for us as they help us in the conversation of food into different products as lactobacillus bacteria converts the milk into curd....
And the microorganisms like virus affects the food as well as our surroundings and are harsh in nature...
(As every thing in universe has a advantage and a disadvantage too)

Answer 2

The beneficial aspects of microorganisms (e.g yeast, lactobacillus etc) is that they help us in converting food material in process of fermentation like the yeast
The harmful aspects of the microorganisms (pathogens) like the viruses, bacteria protozoa etc affect badly to the body. As we can see the virus which is dead without a host(outside a body) but when enters inside the body multiplies like anything. This multiplication of virus is not always identified by the immune system so it is said that virus diseases are more dangerous than any other diseases