Watering plants by using narrow tubes is called ______.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term used to describe the method of watering plants using narrow tubes.

2. **Identifying the Process**: In agricultural practices, there are various methods of irrigation. One common method involves the use of narrow tubes to deliver water directly to the roots of plants.

3. **Recognizing the Term**: The specific term for this method of irrigation is "drip irrigation."

4. **Defining Drip Irrigation**: Drip irrigation is a technique where water is delivered through small tubes directly to the base of the plants. This method ensures that water is used efficiently and reduces wastage.

5. **Conclusion**: Therefore, the answer to the question is that watering plants by using narrow tubes is called **drip irrigation**.

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