Name the scientists who discovered:
Nucleus

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the scientist who discovered the nucleus, which is a vital part of the cell.

2. **Identifying the Scientist**: The nucleus was discovered by a scientist named Robert Brown.

3. **Historical Context**: Robert Brown made this discovery in the year 1831. This information helps to place the discovery in a historical context.

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