A composite organism contains an autotrophic partner that prepares food and a heterotrophic partner that provides shelte
The organism is a lichen. Its algal phycobiont prepares food, while its fungal mycobiont provides shelter and absorbs water and mineral nutrients. Lichens do not grow in polluted areas and therefore serve as pollution indicators.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Viruses Viroids Prions and Lichens