In rigor mortis, muscle tissue becomes locked in position because myosin heads are tightly attached to neighboring actin thin filaments. This lock-up is prevented in living muscle because ordinarily myosin is rapidly displaced from the thin filament by:.A. binding of a new molecule of ATP B. hydrolysis of ATP C. release of ADP after ATP hydrolysis D. release of phosphate after ATP hyrdolysis

The correct answer is option A. binding of a new molecule of ATP.

Explanation:

Actin and myosin are complementary filaments present in muscle, actin is thin and myosin is a thick filament, these two filaments are responsible for the movement by muscle contraction and relaxation. Actin and myosin head shows great affinity towards one another.

Myosin heads are tightly attached to neighboring actin thin filaments due to its affinity to actin, however, myosin at other pockets also show a huge affinity for ATP. If myosin is bound to actin the affinity for ATP is changed and if new ATP bounds to the empty pockets it changes the conformation of myosin and prevents lockup or binding of the actin-myosin protein.