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Answer:
A
Explanation:
Answer is option one, or A
The terminal cisternae releases calcium ion
The terminal cisternae act as calcium storage sites. The calcium ions stored in the terminal cisternae are essential in muscle contraction. The calcium release unit of muscle consists of terminal cisternae of the sarcoplasmic reticulum and it is adjacent transverse or T- tubule that is the invaginated part of the surface membrane.
