Which of the following is non-cellular organisms?

Options

A. Bacteria
B. Fungi
C. Algae
D. Virus

Answer

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks to identify which of the given options is a non-cellular organism. The options provided are bacteria, fungi, algae, and virus.

2. **Define Non-Cellular Organisms**: Non-cellular organisms are entities that do not have a cellular structure. They are typically characterized by their inability to carry out metabolic processes independently and often require a host to replicate.

3. **Analyze Each Option**:
- **Bacteria**: These are unicellular organisms that have a cellular structure. They can live independently and carry out metabolic processes.
- **Fungi**: These are also cellular organisms. They can be unicellular (like yeast) or multicellular (like molds and mushrooms) and have a complex cellular structure.
- **Algae**: Algae are primarily aquatic organisms that can be unicellular or multicellular and possess a cellular structure. They are capable of photosynthesis.
- **Virus**: Viruses are unique in that they are non-cellular. They consist of genetic material (DNA or RNA) encased in a protein coat and require a host cell to replicate. They do not have a cellular structure and are considered obligate parasites.

4. **Identify the Correct Answer**: Based on the definitions and characteristics analyzed, the correct answer is **virus**, as it is the only non-cellular organism among the options provided.

5. **Conclusion**: The answer to the question "Which of the following is non-cellular organisms?" is **virus**.

---