Ornithine cycle occurs in:

Options

A. heart
B. liver
C. muscles
D. kidney

Explanation

**Step-by-Step Solution:**

1. **Understanding the Ornithine Cycle**: The ornithine cycle, also known as the urea cycle, is a biochemical process that converts ammonia, which is toxic at high levels, into urea, a less toxic compound that can be excreted from the body.

2. **Identifying the Location of the Cycle**: The ornithine cycle primarily occurs in the liver. This is where the conversion of ammonia to urea takes place.

3. **Process Overview**: In the liver, ammonia combines with carbon dioxide to form urea. The urea produced is then released into the bloodstream.

4. **Excretion Pathway**: Once in the bloodstream, urea travels to the kidneys, where it is filtered out and eventually excreted from the body through urine.

5. **Conclusion**: Based on the information, the correct answer to the question "Ornithine cycle occurs in:" is the liver.

**Final Answer**: The ornithine cycle occurs in the **liver**.

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