Answer: Can both be helpful and harmful.
Explanation:
Bacteria are unicellular , microscopic organisms that live everywhere. They are both harmful and helpful. Some bacteria invade living cells and cause diseases of different kind, bacteria also cause food contamination thereby making it unfit and harmful when consumed.
Bacteria are also helpful in that they help in digestion , some are present In intestine of animals that aid digestion, bacteria are useful in food manufacturing companies for fermentation of wine, yoghurt e.t.c, they also help in biodegration and decomposition of organic matter thereby releasing nutrients to the soil.
Bacteria are both helpful and harmful.
