Name the chemical substance that fills up the cells of bark?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the chemical substance that fills the cells of bark. This indicates that we need to identify a specific component that is characteristic of bark tissue.

2. **Identifying Bark Composition**: Bark consists of various types of cells, including mature and non-living cells. The primary focus here is on the chemical substances that are present in these cells.

3. **Recognizing the Key Chemical**: The main chemical substance that fills the cells of bark is known as subarine. Subarine is a waxy substance that plays a crucial role in the structure and function of bark.

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