What is the reason for the wide spread of bacteria on our earth?

Bacteria are the most numerous and widespread living organisms on our planet. The breadth of their distribution is associated with several factors:

Bacteria are unpretentious and easily adapt to almost any changes in the environment. Some species are able to exist in extreme habitat conditions.
The tiny size of bacteria allows them to penetrate absolutely any hard-to-reach places, unlike people, animals and plants.
Bacteria multiply at lightning speed, and thousands of new ones replace one dead microorganism.