Point out the odd one-

Options

A. Rennin
B. Secretin
C. Calcitonin
D. Oxytocin

Answer

To solve the question "Point out the odd one," we need to analyze the given options: renin, secretin, calcitonin, and oxytocin.

### Step-by-Step Solution:

1. **Identify the First Option: Renin**
- Renin is a proteolytic enzyme that plays a role in the hydrolysis of proteins, specifically associated with casein, which is a milk protein.

2. **Identify the Second Option: Secretin**
- Secretin is a hormone secreted by the duodenum (part of the alimentary canal). It helps regulate the pH of the small intestine by inhibiting gastric acid secretion and stimulating the production of bicarbonate from the pancreas.

3. **Identify the Third Option: Calcitonin**
- Calcitonin is a hormone produced by the thyroid gland. It helps regulate calcium levels in the blood by lowering them when they are too high.

4. **Identify the Fourth Option: Oxytocin**
- Oxytocin is a hormone produced by the posterior pituitary gland. It is involved in various functions, including stimulating uterine contractions during childbirth and milk ejection during breastfeeding.

5. **Comparison of Options:**
- Renin is an enzyme, while secretin, calcitonin, and oxytocin are all hormones.

6. **Conclusion:**
- The odd one out is **renin**, as it is the only option that is an enzyme, while the others are hormones.

### Final Answer:
The odd one is **renin**.

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