Practice question

Correct option is B, Pressure gradient. In Cardiac Cycle and Regulation, the accurate description is Pressure gradient, and that is what you should commit to memory. Keep the definition tight and the role clear — the functional job described in the stem is exactly what Pressure gradient does in Cardiac Cycle and Regulation. Then Pressure gradient is the answer you can defend. Check yourself by covering the options and writing the answer first, then matching the letter — that builds confidence. If the wording feels dense, translate it into everyday language first, then map that plain sentence back onto Pressure gradient. Remember that physiology questions reward precise language: name the process, the location, and the outcome, then match that to the option text.