Step 1: Understanding the Concept:
Physiological urinalysis crystalluria pH dependencies and neurological spinal reflex arcs.
Step 2: Detailed Explanation:
Matching clinical parameters in List I with descriptions/roots in List II:
- A. Cysteine Crystals: Pathological flat hexagonal crystals formed exclusively in IV. Acidic Urine ($pH < 6.5$) in animals with cystinuria.
- B. Struvite Crystals (Triple Phosphate): Coffin-lid prisms precipitated in III. Alkaline urine ($pH > 7.0$).
- C. Gag Reflex: Mediated by sensory CN IX and motor I. Vagus Nerve (CN X).
- D. Gastrocnemius Reflex: Sciatic/tibial nerve spinal reflex arc segment tested at II. L7 - S1.
Matching sequence: A - IV, B - III, C - I, D - II.
Step 3: Final Answer:
Therefore, the correct matching is A - IV, B - III, C - I, D - II, matching option (A).