Muscle Tissue: Structure, Organization, and Function

Refer to the first three images. These diagrams show the organization of skeletal muscle from the whole muscle down to smaller structures. Which of the following correctly lists the order of organization from largest to smallest?

The fourth image shows the development of a multinucleate skeletal muscle fiber. What is the primary process responsible for the multinucleation of skeletal muscle fibers?

The fifth image shows a skeletal muscle fiber with multiple nuclei and striations. What is the functional significance of having multiple nuclei in skeletal muscle fibers?