True nucleus is not found in :

Options

A. green algae
B. bacteria
C. Entamoeba
D. Spirogyra

Explanation

To answer the question "True nucleus is not found in:", we need to understand the concept of a true nucleus and the types of cells that possess it.

### Step-by-Step Solution:

1. **Understanding True Nucleus**:
- A true nucleus is defined as a membrane-bound structure that contains the genetic material (DNA) of the cell. It is enclosed by a nuclear membrane.

2. **Identifying Cell Types**:
- Cells are classified into two main categories: prokaryotic and eukaryotic.
- **Prokaryotic Cells**: These cells do not have a true nucleus. Instead, their genetic material is not enclosed within a membrane and is typically found in a region called the nucleoid. Examples include bacteria and archaea.
- **Eukaryotic Cells**: These cells have a true nucleus where the genetic material is enclosed within a nuclear membrane. Examples include plant cells, animal cells, fungi, and protists.

3. **Analyzing the Options**:
- The question likely provides several options, including bacteria, green algae, amoeba, and spirogyra.
- **Bacteria**: As prokaryotes, they do not have a true nucleus.
- **Green Algae**: These are eukaryotic and possess a true nucleus.
- **Amoeba**: This is also a eukaryotic organism with a true nucleus.
- **Spirogyra**: This is a type of green algae and is also eukaryotic, possessing a true nucleus.

4. **Conclusion**:
- Since true nuclei are absent in prokaryotic cells and present in eukaryotic cells, the correct answer to the question "True nucleus is not found in:" is **bacteria**.

### Final Answer:
True nucleus is not found in **bacteria**.