Question

whether microorganisms are useful and harmful how explain

Answer 1

Microorganism are usefull in many ways to humans as they are used in indurstry mainly for the production of different compounds such as enzymes, organic acids, antibiotics, vitamins, they help in bakery industries in which chees, yoghurt etc. are produced with help of microbial action and also in alcohol industries. They are also helpfull in wasteproduct degradation as they are also natural decomposers. Now a days researches are being carried for extracting some biofuel from microbes. And they also help in reacillimatisation or barren lands.

Answer 2

some microorganisms r useful as lactobacillus turns the milk into curd .which is useful to us....

and on other hand if the microoorganism enters in our body they will cause many dffrnt types of diseases...which will be harmful for our body...
hope it will help u