Nuclear membrane is absent in:

Options

A. Nostoc
B. Penicillum
C. Agaricus
D. Volvox

Answer

To determine which organism among Nostoc, Penicillium, Agaricus, and Volvox lacks a nuclear membrane, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Nuclear Membrane**:
- The nuclear membrane is a double-layered membrane that surrounds the nucleus in eukaryotic cells, separating it from the cytoplasm.

2. **Identify the Types of Organisms**:
- Organisms can be classified into two main categories based on the presence of a nuclear membrane:
- **Eukaryotes**: Organisms that have a nuclear membrane (e.g., Penicillium, Agaricus, Volvox).
- **Prokaryotes**: Organisms that do not have a nuclear membrane (e.g., Nostoc).

3. **Analyze Each Organism**:
- **Nostoc**: This organism belongs to the kingdom of bacteria and is classified as a cyanobacterium (prokaryote). Therefore, it lacks a nuclear membrane.
- **Penicillium**: This is a type of fungus, which is a eukaryote and has a nuclear membrane.
- **Agaricus**: This is also a fungus (eukaryote) and possesses a nuclear membrane.
- **Volvox**: This organism is classified under the Plantae kingdom and is also a eukaryote with a nuclear membrane.

4. **Conclusion**:
- Since Nostoc is the only organism in the list that is a prokaryote, it is the one that does not have a nuclear membrane.

### Final Answer:
The organism that lacks a nuclear membrane is **Nostoc**.

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