Select the set of correct statements
P. Crista ampullaris is found in saccule and utricle.
Q . Diameter of pupil is regulated by ciliary muscles.
R. Minimum number of neurons in a reflex pathway are two .

Options

A. Q and R is correct
B. P and R is correct
C. Only R is correct
D. Q,R

Answer

To solve the question, we need to analyze each statement one by one to determine which ones are correct.

### Step-by-Step Solution:

1. **Statement P**: "Crista ampullaris is found in saccule and utricle."
- The crista ampullaris is a sensory structure located in the semicircular canals of the inner ear, not in the saccule and utricle. Therefore, this statement is **incorrect**.

2. **Statement Q**: "Diameter of pupil is regulated by ciliary muscles."
- The diameter of the pupil is actually regulated by the iris muscles (specifically the sphincter pupillae and dilator pupillae), not the ciliary muscles. The ciliary muscles are responsible for changing the shape of the lens for focusing. Hence, this statement is also **incorrect**.

3. **Statement R**: "Minimum number of neurons in a reflex pathway are two."
- In a typical reflex arc, there are at least two neurons: a sensory neuron that carries the signal to the spinal cord and a motor neuron that carries the signal away from the spinal cord to the effector (muscle or gland). This statement is **correct**.

### Conclusion:
- The only correct statement is **R**.

### Final Answer:
The correct set of statements is **only R**.

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