If ATP Is Present, Why Do Actin and Myosin Not

Multiple Choice

If ATP is present, why do actin and myosin not spontaneously interact with each other in the absence of nerve stimulation? Select all that apply.

A) ATP is blocked by an ATPase in the absence of Ca²⁺.
B) Myosin and actin require Ca²⁺ to interact.
C) ATP is bound to the myosin binding site on actin.
D) The actin-binding site for myosin is blocked by troponin/tropomyosin complex.