Which of these statements is a correct ?

Options

A. All arteries carry purified blood
B. Urine of all vertebrates is similar
C. All motor fibres leave spinal cord via ventral root
D. Red blood corpuscles of all vertebrates are nucleated

Answer

To determine which statement is correct, let's analyze each option step by step:

1. **Option 1: All arteries carry purified blood.**
- **Analysis:** While it is true that most arteries carry oxygenated blood (which can be considered "purified"), the pulmonary artery is an exception as it carries deoxygenated blood from the heart to the lungs for oxygenation. Therefore, this statement is incorrect.

2. **Option 2: Urine of all vertebrates is similar.**
- **Analysis:** This statement is false. The urine composition varies among vertebrates. For example, fish excrete ammonia, mammals primarily excrete urea, and birds excrete uric acid. Therefore, this statement is also incorrect.

3. **Option 3: All motor fibers leave the spinal cord via the ventral root.**
- **Analysis:** This statement is correct. Motor neurons exit the spinal cord through the ventral root, which is responsible for carrying motor signals to the muscles. Thus, this statement is accurate.

4. **Option 4: RBC of all vertebrates are nucleated.**
- **Analysis:** This statement is incorrect. In mammals, red blood cells (RBCs) are non-nucleated, while in other vertebrates, such as birds and reptiles, the RBCs are nucleated. Therefore, this statement is also incorrect.

**Conclusion:** The only correct statement among the options provided is that all motor fibers leave the spinal cord via the ventral root.

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