Answer the following question given this paragraph: 

A lichen is a mutualistic relationship between a fungus and a photosynthetic organism. The other organism is usually a cyanobacterium or green alga. The fungus grows around the bacterial or algal cells. The fungus benefits from the constant supply of food produced by the photosynthesizer. The photosynthesizer benefits from the water and nutrients absorbed by the fungus. Figure below shows lichen growing on a rock.


Q: The fungus benefits from the constant supply of food produced by what?


A:
the photosynthesizer