Some of them are benificial while others are not just like the bacterias on soil,they help to decompose the dead animals,plants or humans so it gets back on land. The good bacterias on our body also help to defend our health from diseases. Some bacterias also have a big part oon some environmental cycles like nitrogen cycle and many more. However,some microorganisms also bring harm. Germs everywhere are source of diseases. Viruses also cause diseases. Therefore not all microorganisms are benificial nor harmful.
