AIIMS 2019 Zoology Role of Calcium Assertion Reason Question

Option B is correct because both the assertion and reason are true: calcium ions (Ca²⁺) are indeed essential for skeletal muscle contraction, and acetylcholine (ACh) is released at the neuromuscular junction to initiate this process. However, the reason does not directly explain the assertion, as it does not detail how calcium facilitates muscle contraction after ACh binds to receptors. Option A is incorrect because, while both statements are true, the reason does not justify the assertion. Option C is incorrect because both statements are true, and option D is incorrect as both statements are factual. Understanding the role of Ca²⁺ in muscle contraction and the function of ACh at the neuromuscular junction is crucial for grasping muscle physiology.