Which statement is true concerning the development of muscle?

You're on a roll — The question asks which statement is true concerning the development of muscle. Step 1: Analyze option A. Epaxial muscles are derived from the epimere of the somites and form the muscles of the back. They are innervated by the dorsal rami* of the spinal nerves. Ventral rami innervate hypaxial muscles (body wall and limb muscles). Therefore, option A is incorrect. Step 2: Analyze option B. During embryonic development, the paraxial mesoderm segments into somites. Each somite differentiates into a sclerotome (forms vertebrae and ribs), a dermatome (forms dermis), and a myotome* (forms skeletal muscle). Therefore, option B is correct. Step 3: Analyze option C. The paraxial mesoderm*, a specific part of the mesoderm, is divided into somites. The entire mesoderm germ layer also includes intermediate mesoderm and lateral plate mesoderm, which do not form somites. Therefore, option C is incorrect as it is too general. Step 4: Analyze option D. Skeletal muscles are derived from the paraxial mesoderm. However, cardiac muscle develops from the splanchnic lateral plate mesoderm, and most smooth muscle also develops from the lateral plate mesoderm or local mesenchyme. Therefore, option D is incorrect because not all* muscles are derived from paraxial mesoderm. The correct option is B. Myotome forms muscle. Drop the next question!