Assertion : In mammals, complex respiratory system has developed.
Reason : Mammalian skin is impermeable to gases.

Options

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

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states: "In mammals, a complex respiratory system has developed."
- This is true. Mammals have evolved a sophisticated respiratory system that includes lungs, which allow for efficient gas exchange. The complexity of this system is necessary to meet the high metabolic demands of mammals.

**Hint:** Consider the structure and function of the mammalian respiratory system.

### Step 2: Understand the Reason
The reason states: "Mammalian skin is impermeable to gases."
- This is also true. Mammalian skin has a thick outer layer (epidermis) that prevents the diffusion of gases. As a result, mammals cannot rely on cutaneous respiration (breathing through the skin) as some other organisms do.

**Hint:** Think about the differences in respiratory mechanisms between mammals and other organisms.

### Step 3: Analyze the Relationship
Now we need to determine if the reason given supports the assertion.
- The reason explains why mammals need a complex respiratory system: because their skin does not allow for gas exchange. Therefore, they must rely on lungs and other respiratory structures to obtain oxygen and expel carbon dioxide.

**Hint:** Consider how the inability to respire through the skin necessitates the development of a more complex respiratory system.

### Step 4: Conclusion
Both the assertion and the reason are true, and the reason correctly explains the assertion. Thus, the correct answer is that both statements are true and the reason is a valid explanation for the assertion.

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