By nature heparin, bradykinin and seratonin respectively are  

Options

A. vaso constrictor, vasodilator and anti coagulant
B. anticoagulant, vasodilator and vaso constrictor
C. vasodilator, anticoagulant & vasocontrictor
D. vasodilator, vasoconstrictor & anticoagulant

Answer

To answer the question about the nature of heparin, bradykinin, and serotonin, we will analyze each substance step by step.

### Step 1: Identify the nature of Heparin
- **Heparin** is known as an **anticoagulant**. It prevents blood clotting by inhibiting the coagulation process. This is crucial in medical settings to prevent thrombosis.

### Step 2: Identify the nature of Bradykinin
- **Bradykinin** is a peptide that promotes **vasodilation**, which is the widening of blood vessels. This process increases blood flow to tissues, especially during inflammatory responses, and can lower blood pressure.

### Step 3: Identify the nature of Serotonin
- **Serotonin**, also known as 5-hydroxytryptamine, acts primarily as a **vasoconstrictor**. It causes the constriction of blood vessels, which can lead to an increase in blood pressure. Additionally, serotonin has roles in mood regulation and cognitive functions.

### Conclusion
Based on the analysis:
- Heparin: Anticoagulant
- Bradykinin: Vasodilator
- Serotonin: Vasoconstrictor

Thus, the correct sequence is:
**Anticoagulant (Heparin), Vasodilator (Bradykinin), Vasoconstrictor (Serotonin)**.

### Final Answer
The correct option is: **Anticoagulant, Vasodilator, Vasoconstrictor**.

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