Fill in the blanks. :Plant parts which cannot be eaten are called ___________parts.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks us to fill in the blank regarding plant parts that cannot be eaten.

2. **Identifying Plant Parts**: We need to think about which parts of a plant are typically not consumed by humans. Common examples include branches, flowers, and raw plant materials.

3. **Understanding Non-Edibility**: The reason certain plant parts cannot be eaten is due to the absence of specific enzymes in our body that help break down these parts. For instance, cellulose is a component found in many plant parts that humans cannot digest.

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