QRS complex represents:
Pick B: Ventricular depolarization. Thinking about Cardiac Cycle and Regulation in a practical way — what the structure does, or what the process achieves — leads you here. Clinically and academically, the same logic shows up again and again: Ventricular depolarization is the option that correctly names the structure, process, or principle asked for in Cardiac Cycle and Regulation. Hence Ventricular depolarization is correct. Treat this as a building block for the rest of Cardiac Cycle and Regulation; neighbouring topics often reuse the same principle. Keep a one-line summary card for this idea and revisit it before the paper; short, repeated review beats long cramming sessions.
Ref: Animal physiology is Unit 7 of the CSIR NET Life Science Syllabus, covering core body systems. It accounts for roughly 10% of the total marks in Sections B and C.