Question

What are the beneficial or useful bacterias ? please answer in brief........

Answer 1

Probiotics are live bacteria and yeasts that are good for you, especially your digestive system. We usually think of these as germs that cause diseases. But your body is full of bacteria, both good and bad. Probiotics are often called bacteria because they help keep your gut healthy.
Hope it help you.

Answer 2

Bacteria are micro organisms . Bacteria like lactobacillus bacteria helps in transformation of milk to curd . they Act as scavengers in some cases