Non-membranous organelles are

Options

A. Centrioles
B. Ribosomes
C. Nucleolus
D. All of these

Answer

### Step-by-Step Solution:

1. **Definition of Non-Membranous Organelles**: Non-membranous organelles are cellular structures that do not have a surrounding membrane. They are involved in various cellular functions and are found in both prokaryotic and eukaryotic cells.

2. **Examples of Non-Membranous Organelles**: The key examples of non-membranous organelles include:
- **Ribosomes**: These are the sites of protein synthesis and are found in both prokaryotic and eukaryotic cells.
- **Centrioles**: These are involved in cell division and are found in eukaryotic cells.
- **Nucleolus**: This is a structure within the nucleus that is involved in ribosome production and is also found in eukaryotic cells.

3. **Presence in Eukaryotes**: In eukaryotic cells, all three organelles (centrioles, ribosomes, and nucleolus) are present and classified as non-membranous organelles.

4. **Presence in Prokaryotes**: In prokaryotic cells, ribosomes are present, but centrioles and nucleolus are absent. Instead, prokaryotes have a nucleoid region, which is not membrane-bound.

5. **Conclusion**: Therefore, when considering non-membranous organelles in eukaryotic cells, the answer is "all of these" (centrioles, ribosomes, nucleolus). In prokaryotic cells, the answer is only "ribosomes".

### Final Answer:
Non-membranous organelles include centrioles, ribosomes, and nucleolus. In eukaryotes, all three are present, while in prokaryotes, only ribosomes are present.

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