The periodic departure and return is known as

Options

A. Migration
B. Immigration
C. Emigration
D. Mutation

Answer

To solve the question "The periodic departure and return is known as," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**: We need to analyze the options given: migration, immigration, emigration, and mutation.

2. **Define Migration**: Migration refers to the periodic movement of organisms from one place to another and back again. This movement is often seasonal and can involve various species, including birds, mammals, and fish.

3. **Consider Immigration**: Immigration is the process where new individuals move into a population. It does not involve a return to the original location.

4. **Consider Emigration**: Emigration is the departure of individuals from one population to another. Like immigration, it does not imply a return.

5. **Consider Mutation**: Mutation refers to changes in the genetic material of an organism. This is unrelated to movement or periodicity.

6. **Identify the Correct Answer**: Since the question specifies "periodic departure and return," the correct term that encompasses this definition is migration.

### Final Answer:
The periodic departure and return is known as **migration**.

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