In older portion of roots and woody stems, the exchange of gases takes place through small openings called _______.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of the small openings in the older portions of roots and woody stems that facilitate gas exchange.

2. **Identifying the Structures**: In plants, particularly in older roots and woody stems, there are specialized structures that allow for gas exchange. These structures are different from stomata, which are found in leaves.

3. **Defining the Term**: The small openings responsible for gas exchange in the older parts of roots and woody stems are known as "lenticels."

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