Which of the following is NOT a part of a stream? Plain Run Pool Riffle

The correct answer is: Plain.In the context of a stream, the terms "run," "pool," and "riffle" refer to specific features or sections within the stream. A "run" is a smooth, uninterrupted section of the stream, a "pool" is a deep, slow-moving section, and a "riffle" is a shallow, fast-moving section with rocks or gravel. On the other hand, a "plain" is a flat, level area of land, which is not a specific part of a stream.