cells that have membrane bound nucleus includes

Options

A. Rhizobium
B. Meristem
C. Mature sieve tube
D. Nostoc

Answer

To determine which cells have a membrane-bound nucleus, we will analyze each of the given options one by one.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for cells that have a membrane-bound nucleus. This means we are looking for eukaryotic cells, as they possess a true nucleus enclosed by a nuclear membrane.

2. **Analyzing Option A: Rhizobium**:
- Rhizobium is a type of bacteria.
- Bacteria are classified as prokaryotic cells, which do not have a membrane-bound nucleus.
- Therefore, Rhizobium does not have a membrane-bound nucleus.
- **Conclusion**: Incorrect option.

3. **Analyzing Option B: Meristem**:
- Meristem is a type of plant tissue.
- Plant cells are eukaryotic, meaning they have a true nucleus that is membrane-bound.
- Since meristematic cells can differentiate and divide, they possess a well-developed membrane-bound nucleus.
- **Conclusion**: Correct option.

4. **Analyzing Option C: Mature Sieve Tubes**:
- Mature sieve tubes are specialized cells found in the phloem of plants.
- Although they are living cells, mature sieve tubes lack a nucleus at maturity.
- Therefore, they do not possess a membrane-bound nucleus.
- **Conclusion**: Incorrect option.

5. **Analyzing Option D: Nostoc**:
- Nostoc is a type of cyanobacteria.
- Like Rhizobium, it is also classified as a prokaryotic organism.
- Prokaryotic cells do not have a membrane-bound nucleus.
- **Conclusion**: Incorrect option.

### Final Answer:
The only cell type from the options provided that has a membrane-bound nucleus is **B: Meristem**.

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