In Whittaker's classification Archaebacteria and nitrogen fixing algae are placed under

Options

A. Plantae
B. Fungi
C. Monera
D. Protista

Answer

**Step-by-Step Solution:**

1. **Understanding Whittaker's Classification**: Whittaker proposed a five-kingdom classification system for living organisms, which includes Monera, Protista, Fungi, Plantae, and Animalia.

2. **Identifying the Kingdoms**:
- Kingdom Monera includes prokaryotic organisms, which are unicellular and lack a defined nucleus.
- Kingdom Protista consists of mostly unicellular eukaryotic organisms.
- Kingdom Fungi includes multicellular eukaryotic organisms that absorb nutrients.
- Kingdom Plantae comprises multicellular eukaryotic organisms that perform photosynthesis.
- Kingdom Animalia includes multicellular eukaryotic organisms that are heterotrophic.

3. **Placing Archaebacteria**: Archaebacteria are a type of prokaryotic organism. They are known for their unique characteristics, such as the absence of peptidoglycan in their cell walls. Therefore, they are classified under the Kingdom Monera.

4. **Placing Nitrogen-Fixing Algae**: Nitrogen-fixing algae, commonly referred to as Cyanobacteria, are also prokaryotic. They are capable of photosynthesis and nitrogen fixation. Like Archaebacteria, they are also placed in the Kingdom Monera.

5. **Conclusion**: Both Archaebacteria and nitrogen-fixing algae (Cyanobacteria) are classified under the Kingdom Monera in Whittaker's classification system.

**Final Answer**: Archaebacteria and nitrogen-fixing algae are placed under the Kingdom Monera.

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