Identify the organism which has prokaryotic cell structure and autotrophic mode of nutrition.

Options

A. Euglena
B. Mycoplasma
C. Cyanobacteria
D. Rhizobium

Answer

**Step-by-Step Solution:**

1. **Understanding Prokaryotic Cells**: Prokaryotic cells are unicellular organisms that lack a defined nucleus and membrane-bound organelles. They are generally smaller and simpler than eukaryotic cells.

2. **Identifying Autotrophic Nutrition**: Autotrophic organisms are capable of producing their own food, typically through processes like photosynthesis or chemosynthesis. This means they do not rely on other organisms for their nutritional needs.

3. **Analyzing the Options**:
- **Euglena**: This organism is classified under the Protista kingdom. While it is unicellular, it is primarily heterotrophic, meaning it relies on other organisms for food.
- **Mycoplasma**: This is a type of bacteria but is not autotrophic. It is known for being pathogenic and does not produce its own food.
- **Cyanobacteria**: These are prokaryotic organisms that can perform photosynthesis, using sunlight to produce food. They are also known for their green pigment and can be considered autotrophic.
- **Rhizobium**: This is a soil bacterium known for fixing nitrogen. It does not produce its own food and is not classified as autotrophic.

4. **Conclusion**: Based on the analysis, the organism that has a prokaryotic cell structure and an autotrophic mode of nutrition is **Cyanobacteria**. They are unicellular, can perform photosynthesis, and do not depend on other organisms for their food.

**Final Answer**: Cyanobacteria

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