Assertion (A): Cross breeding of dairy animals increases the productivity of milk.
Reason (R): Lactation period of dairy animals can be increased by cross breeding.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true, but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true

Explanation

To analyze the given assertion and reason, let's break it down step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Cross breeding of dairy animals increases the productivity of milk."
- Cross breeding involves mating individuals from different breeds to produce offspring with desirable traits. In dairy animals, this can lead to improved milk yield.

2. **Understanding the Reason (R)**:
- The reason states that "Lactation period of dairy animals can be increased by cross breeding."
- The lactation period is the time during which a female animal produces milk after giving birth. An increase in this period means that the animal will produce milk for a longer duration.

3. **Connecting Assertion and Reason**:
- The assertion claims that cross breeding increases milk productivity, while the reason suggests that this is due to an increase in the lactation period.
- If cross breeding leads to a longer lactation period, it logically follows that the overall milk production would also increase.

4. **Evaluating the Truth of Both Statements**:
- Both the assertion and the reason are true. Cross breeding has been shown to enhance milk yield in dairy animals, and it can also contribute to an extended lactation period.

5. **Conclusion**:
- Since both the assertion and the reason are true, and the reason provides a correct explanation for the assertion, we conclude that the assertion is correct and the reason is the correct explanation for it.

### Final Answer:
Both the assertion (A) and the reason (R) are true, and R is the correct explanation of A.

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