5.1 If the muscle has an epiphysium, it is a complete muscle.
5.2 Sacroplasm would be the cytoplasm of a muscle fiber.
5.3 b.d.a.c.
5.4 The power stroke.
5.5 It is starting contraction.
5.6 b.e.f.c.d.a.g.
5.7 Ca2+ ions move through membrane via diffusion, passive transport.