Name the transcriptionally active region of chromatin in a nucleus.

Explanation

**Step-by-Step Solution:**

1. **Understanding Chromatin**: Chromatin is the complex of DNA and proteins found in the nucleus of eukaryotic cells. It exists in two forms: euchromatin and heterochromatin.

2. **Identifying Chromatin Types**:
- **Euchromatin**: This is the less condensed form of chromatin. It is loosely packed, which allows for the transcription of genes. This region is transcriptionally active.
- **Heterochromatin**: This is the more condensed form of chromatin. It is tightly packed and generally transcriptionally inactive.

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