Assertion: Migration is an important factor which determines both population size and population density.
Reason: In migration, a major part of population goes from one area to another area.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true and the Reason is not the correct explanation of the Assertion.
C. If Assertion is true but the Reason is false
D. If both Assertion and Reason are false.

Explanation

To solve the question, let's break it down into steps:

### Step 1: Understand the Assertion
The assertion states that "Migration is an important factor which determines both population size and population density."

- **Explanation**: Migration refers to the movement of individuals from one location to another. This movement can significantly impact the number of individuals in a population (population size) and how closely packed they are in a given area (population density).

### Step 2: Understand the Reason
The reason provided is "In migration, a major part of the population goes from one area to another area."

- **Explanation**: This statement explains what migration entails. When individuals migrate, they leave one area and settle in another, which can lead to changes in the population size and density of both the originating and receiving areas.

### Step 3: Analyze the Relationship Between Assertion and Reason
Now, we need to determine if the reason correctly explains the assertion.

- **Explanation**: Since migration involves a significant movement of individuals, it directly affects the population size (as individuals leave or join) and the population density (as the number of individuals per unit area changes). Therefore, the reason does indeed provide a correct explanation for the assertion.

### Step 4: Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion.

- **Final Answer**: The correct option is that both the assertion and reason are true, and the reason is the correct explanation for the assertion.

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