Question

what is the association of fungi and cyanobacteria known as? how it is useful to us?

Answer 1

combination of Fungi and cyanobacteria is called lichens or combination of Algae and fungi

Lichens are organisms that are formed by the association of fungi and algae where both the organisms are mutually benefited. 

Answer 2

The combination of fungi and cyanobacteria is called lichens.

Cyanobacteria also called cyanophyta and also create food by photosynthesis with the presence of chlorophyll

Lichens are slow growing plants which grow on moist surfaces or dead plants and leaves.