Apart from plants and animals, microbes form a permanent biotic component in an ecosystem. While plants have been referred to as autotrophs and animals as heterotrophs. What are microbes referred to as? How do the microbes fulfill their energy requirements? 

Explanation

### Step-by-Step Solution:

1. **Understanding the Classification of Organisms**:
- Organisms are classified based on their nutritional habits into two main categories: autotrophs and heterotrophs.
- Autotrophs are organisms that can produce their own food (e.g., plants), while heterotrophs are organisms that rely on other organisms for their food (e.g., animals).

2. **Identifying Microbes in the Ecosystem**:
- Microbes, which include bacteria, fungi, and some protists, are also a crucial part of the ecosystem.
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