When the root is swollen in the middle and tapers gradually at both ends, it is called ..........

Explanation

**Step-by-Step Solution:**

1. **Understanding Root Structure**: The question describes a specific type of root that is swollen in the middle and tapers at both ends. This indicates a particular morphology of the root.

2. **Identifying the Type of Root**: The root being described is known as a "Fusiform Root." This term refers to roots that are broader in the middle and taper off towards both ends.

3. **Function of Fusiform Roots**: Fusiform roots are modified roots that primarily serve as storage organs. They store nutrients such as carbohydrates and proteins, which are essential for the plant's growth and development.

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