Question

what is lichen?mention its special features

Answer 1

lichen are composite organisms which arises from algae and cyanobacteria living among filament multiple fungi

Answer 2

Lichen is a mutalistic relationship between algae and fungi. It forms a small leaf-like or crust like growth on rocks and walls and trees.  

In this association, both organisms use each other as substrate and benefit each other. Algae prepare food by photosynthesis and fungi takes carbohydrates from the food algae prepare and in return provide protection to algae.