Archaebacteria are

Options

A. heterotrophic and anaerobic
B. chemotrophic
C. decomposers and mineralisers
D. all of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Archaebacteria:**
- Archaebacteria are a diverse group of prokaryotic organisms. They are characterized by the absence of membrane-bound organelles and a true nucleus.

2. **Characteristics of Archaebacteria:**
- They are known to be one of the oldest living organisms on Earth and can survive in extreme environments.

3. **Types of Archaebacteria:**
- There are three major types of Archaebacteria:
- **Thermoacidophiles:** These thrive in high-temperature and acidic conditions.
- **Halophiles:** These live in saline (salty) environments.
- **Methanogens:** These produce methane by decomposing organic matter.

4. **Analyzing the Options:**
- **Option A: Heterotropic and Anaerobic**
- Many Archaebacteria, especially methanogens, are heterotrophic (cannot produce their own food) and anaerobic (thrive in the absence of oxygen). This statement is correct.

- **Option B: Chemotropic**
- Some Archaebacteria, like thermoacidophiles, can utilize chemical energy to produce their own food. Therefore, this statement is also correct.

- **Option C: Decomposers and Mineralizers**
- Methanogens act as decomposers and mineralizers by breaking down organic matter and releasing methane. This statement is correct as well.

5. **Conclusion:**
- Since all the statements about Archaebacteria are true, the correct answer is **Option D: All of the above.**

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