Which process must occur for a muscle to be able to relax? a. the concentration of calcium in the myofibril must decrease. b. the amount of atp in the neuromuscular junction must increase. c. a nerve must initiate an action potential in the muscle fiber. d. myosin and actin must attach to each other.

The correct option is A. which is the concentration of calcium in the myofibril must decrease.

A. which is the concentration of calcium in the myofibril must decrease.

Explanation:

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"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."