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Physiology · Muscle physiology
Sample itemWhat ion binds troponin to initiate skeletal muscle contraction?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
C. Calcium
The relevant Muscle physiology principle makes Calcium the best answer because it directly explains the structure or physiological response in the stem.
Option by option
A. Magnesium
Magnesium is not supported by the key clue provided in this item.
B. Sodium
Sodium does not correspond to the structure or response being tested.
C. Calcium (correct)
Correct. Calcium directly follows from the core muscle physiology relationship.
D. Chloride
Chloride is associated with a different anatomical or physiological role.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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