What is mutualism ? Mention any two examples where the organisms involved are commercially exploited in agriculture.

Explanation

### Step-by-Step Solution:

1. **Definition of Mutualism**:
Mutualism is a type of symbiotic relationship between two organisms where both parties benefit from the interaction. In this relationship, one organism gains advantages such as nutrients or shelter, while the other organism also receives benefits, which can include food or other resources.

2. **Examples of Mutualism**:
- **Lichens**: Lichens are a symbiotic association between fungi and algae (or cyanobacteria). In this relationship, the fungi provide minerals, shelter, and moisture to the algae, while the algae produce food through photosynthesis, which is shared with the fungi.
- **Mycorrhiza**: Mycorrhiza refers to the symbiotic relationship between fungi and the roots of higher plants. The fungi enhance the plant's ability to absorb water and essential minerals from the soil, while the plant supplies carbohydrates and nutrients to the fungi.
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