Assertion: Heparin is an anticoagulant found in mammals.
Reason: Heparin prevents the conversion of prothrombin to thrombin

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that "Heparin is an anticoagulant found in mammals."
- Heparin is indeed a well-known anticoagulant, which means it prevents blood from clotting. It is produced in the body, primarily by the liver and is present in various tissues.

2. **Understanding the Reason**: The reason given is "Heparin prevents the conversion of prothrombin to thrombin."
- To understand this, we need to look at the blood clotting mechanism. Prothrombin is a protein that is converted into thrombin, which is an enzyme that plays a crucial role in blood coagulation.

3. **Blood Clotting Mechanism**: The conversion of prothrombin to thrombin is facilitated by an enzyme called thrombokinase in the presence of calcium ions. Thrombin then converts fibrinogen into fibrin, leading to the formation of a blood clot.

4. **Role of Heparin**: Heparin acts as an anticoagulant by inhibiting thrombokinase, which prevents the conversion of prothrombin to thrombin. Therefore, it effectively stops the clotting process.

5. **Conclusion**: Since both the assertion and reason are true, and the reason correctly explains the assertion, we conclude that the correct answer is that both statements are true and the reason is the correct explanation of the assertion.

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

---