Assertion :- The aquatic mammals like Dolphins whales etc. do not contain gill slits.
Reason : Their adaptation to aquatic life secondary.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is a not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are false.

Answer

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

### Step 1: Understand the Assertion
The assertion states that aquatic mammals like dolphins and whales do not contain gill slits. This is true because these mammals are not fish; they are mammals that have adapted to living in water. Instead of gills, they possess lungs that allow them to breathe air.

**Hint:** Think about the respiratory systems of different animal groups and how they adapt to their environments.

### Step 2: Understand the Reason
The reason provided is that their adaptation to aquatic life is secondary. This means that these mammals evolved from land-dwelling ancestors and adapted to a life in water over time. This statement is also true, as the ancestors of dolphins and whales were terrestrial mammals.

**Hint:** Consider the evolutionary history of mammals and how certain traits may change as species adapt to new environments.

### Step 3: Evaluate the Relationship
Now, we need to evaluate whether the reason is a correct explanation of the assertion. Since the assertion is about the lack of gill slits in aquatic mammals and the reason explains that these mammals adapted from land-dwelling ancestors, it supports the assertion. The adaptation to an aquatic lifestyle led to the development of lungs instead of gills.

**Hint:** Think about how evolutionary adaptations can lead to significant changes in anatomy and physiology.

### Step 4: Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Therefore, the correct conclusion is that both statements are true, and the reason is a correct explanation of the assertion.

**Final Answer:** Both the assertion and reason are true, and the reason is a correct explanation of the assertion.