Cyclosis is absent in

Options

A. Diatoms
B. Eubacteria
C. Algae
D. Plantae

Answer

**Step-by-Step Solution:**

1. **Understanding Cyclosis**: Cyclosis refers to the streaming movement of the cytoplasm within a cell, which is essential for various metabolic processes. This movement is facilitated by the cytoskeleton, which includes structures like intermediate filaments.

2. **Identifying the Types of Organisms**: Organisms can be classified into two main categories based on their cellular organization: prokaryotes and eukaryotes. Prokaryotes lack a well-defined nucleus and cytoskeleton, while eukaryotes have a defined nucleus and possess a cytoskeleton.

3. **Cytoskeleton Presence**: The cytoskeleton, which is crucial for cyclosis, is present in eukaryotic cells. In contrast, prokaryotic cells do not have a cytoskeleton, which means cyclosis cannot occur in these organisms.

4. **Analyzing the Options**: The question provides four options, and we need to determine which one does not exhibit cyclosis:
- **Diatoms**: These are unicellular eukaryotic organisms belonging to the kingdom Protista. They have a cytoskeleton and can perform cyclosis.
- **Eubacteria**: This group falls under the kingdom Monera and consists of prokaryotic organisms. Since they lack a cytoskeleton, cyclosis is absent in eubacteria.
- **Algae**: Algae are primarily eukaryotic organisms found in the kingdom Plantae. They possess a cytoskeleton and can perform cyclosis.
- **Fungi**: Fungi are also eukaryotic organisms and have a cytoskeleton, allowing for cyclosis.

5. **Conclusion**: Based on the analysis, eubacteria, being prokaryotic, do not have a cytoskeleton and therefore do not exhibit cyclosis. Thus, the answer to the question "Cyclosis is absent in" is **Eubacteria**.