Assertion: Sharks are said to be ammonotelic animals.
Reason: Sharks can retain considerable amounts of ammonia in their blood.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. if both assertion and reason are true but reason is not the correct explanation of assertion.
C. if assertion is true but reason is false
D. if both assertion and reason are false.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "Sharks are said to be ammonotelic animals." Ammonotelic animals excrete ammonia as their primary nitrogenous waste.

2. **Evaluating the Assertion**: Sharks are aquatic animals, but they do not excrete ammonia. Instead, they primarily excrete urea, which classifies them as ureotelic animals. Therefore, the assertion is **false**.

3. **Understanding the Reason**: The reason provided states that "Sharks can retain considerable amounts of ammonia in their blood."

4. **Evaluating the Reason**: While sharks do have some ammonia in their blood, they cannot afford to retain large amounts of it because excreting ammonia requires a significant amount of water. Sharks need to conserve water to maintain their osmotic balance, so they do not retain considerable amounts of ammonia. Thus, the reason is also **false**.

5. **Conclusion**: Since both the assertion and the reason are false, the correct answer is that both statements are false.

**Final Answer**: Both assertion and reason are false.

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