Give the technical term for the darkly stained and transcriptionally inactive part of chromatin.

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. **Defining Transcription**: Transcription is the process by which the information in a DNA strand is copied into messenger RNA (mRNA). This process is crucial for gene expression.

3. **Identifying the Characteristics of Heterochromatin**: Heterochromatin is a tightly packed form of DNA, which makes it transcriptionally inactive. This means that the genes located in these regions are not expressed or transcribed into mRNA.

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