After the discovery of living cell Robert Brown discovered

Options

A. Nucleolus
B. Nucleus
C. Ribosomes
D. Chromatin material

Answer

**Step-by-Step Solution:**

1. **Identify the Key Scientists**: The question asks about Robert Brown and his discoveries after the discovery of living cells by Robert Hooke. It's important to differentiate between the contributions of these two scientists.

2. **Understand Robert Hooke's Contribution**: Robert Hooke is credited with the discovery of the cell in 1665 when he observed cork under a microscope and coined the term "cell."

3. **Focus on Robert Brown's Discovery**: Robert Brown, a botanist, is known for discovering the nucleus in plant cells in 1831. This was a significant advancement in cell biology, as the nucleus is a critical component of eukaryotic cells.

4. **Clarify Other Discoveries**: The transcript mentions other discoveries related to cell components:
- The nucleolus was discovered by Phyllis Fontana.
- Ribosomes were discovered by George Palade.
- Chromatin material, which consists of DNA and proteins, is not attributed to Robert Brown.

5. **Conclusion**: Based on the information, Robert Brown's significant discovery after the living cell was the nucleus. Therefore, the correct answer to the question is that Robert Brown discovered the nucleus.

**Final Answer**: Robert Brown discovered the nucleus.

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