Why are some substances biodegradable and some non-biodegradable?

Explanation

### Step-by-Step Solution:

1. **Definition of Biodegradable Substances**:
- Biodegradable substances are materials that can be broken down or decomposed by microorganisms such as bacteria and fungi. This process involves the natural decay of organic matter.

2. **Examples of Biodegradable Substances**:
- Common examples include paper, vegetable waste, cotton, and food scraps. These materials can be easily decomposed by microorganisms in the environment.

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