A periodic migrant is

Options

A. Locust
B. Elk
C. Whale
D. Golden Plover.

Answer

**Step-by-Step Solution:**

1. **Understanding Periodic Migration:**
- Periodic migration refers to the occasional movement of a species from one habitat to another, typically in response to environmental conditions or population dynamics.

2. **Analyzing the Options:**
- The options provided are locust, elk, whale, and golden plover. We need to determine which of these undergoes periodic migration.

3. **Identifying Characteristics of Each Option:**
- **Locust:** Known for occasional migrations, particularly when there is a significant increase in population.
- **Elk:** Generally migrates seasonally but not periodically in the same sense as locusts.
- **Whale:** Migrates seasonally for breeding and feeding but does not fit the definition of periodic migration.
- **Golden Plover:** Also migrates seasonally and does not exhibit periodic migration.

4. **Focusing on Locusts:**
- Locusts undergo periodic migration when their population increases significantly. This migration is often triggered by environmental factors, such as hot weather, which leads to the development of migratory forms from nymphs (young locusts).

5. **Conclusion:**
- Based on the characteristics and behaviors of the organisms listed, the only option that fits the definition of a periodic migrant is the locust.

**Final Answer:** A periodic migrant is the locust.

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