If i have a tree in my back yard, and in the middle of the summer, the leaves start turning and falling, does that mean the tree is dying?

Do the following statements describe actin, myosin, both of the proteins or neither of the proteins? (a) contains a binding site for calcium (b) found in the i band (c) exists in a globular (g) form and a filamentous (f) form (d) contains a binding site for atp (e) is a component of the thin filament (f) is a component of the thick filament