Respiration is completely absent in

Options

A. Bacteriophage
B. Cyanobacteria
C. Chlorella
D. Spirulina

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks which organism among the given options does not perform respiration at all.

2. **Analyze the Options**:
- **Bacteriophage**: These are viruses that infect bacteria. They do not have a cellular structure and do not carry out metabolic processes like respiration.
- **Cyanobacteria**: These are photosynthetic bacteria that perform respiration. They can convert sunlight into energy and also respire.
- **Chlorella**: This is a type of green algae that performs photosynthesis and respiration.
- **Spirulina**: Another type of cyanobacteria that also performs photosynthesis and respiration.

3. **Evaluate Each Option**:
- Bacteriophages do not have a mechanism for respiration as they are viruses and rely on host bacteria for replication.
- Cyanobacteria, Chlorella, and Spirulina all have metabolic processes that include respiration.

4. **Conclusion**: Since bacteriophages do not perform respiration, the correct answer is **bacteriophage**.

**Final Answer**: Respiration is completely absent in **bacteriophage**.

---