Answer the following question given this paragraph: 

A lichen is an organism that results from 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: How does the fungus benefit from the photosynthesizer?

 Choices:

- shade

- protection from chemicals

- supply of carbon dioxide

- supply of food

A:
supply of food
