â¢ In grade 4 mathematics, seven of the 50 states included in the analysis set standards for proficiency (as measured on the NAEP scale) that were lower than the Basic performance on NAEP, 42 were in the NAEP Basic range, and one in the Proficient range. In grade 8 mathematics, 12 of 49 states included in the analysis
noun, plural: skeletal muscles. A voluntary, striated (vertebrate) muscle that is associated with the skeleton, and thus move parts of the skeletal system. Supplement. The muscular system of the vertebrates is comprised of various muscles.
The functional units of skeletal muscle are not individual muscle fibers, but larger systems called motor units. The motor unit consists of a motor neuron and the group of skeletal muscle fibers which it innervates. A single skeletal muscle is composed of many thousands to millions of long, narrow contractile cells called muscle fibers (Fig-1). These fibers are clustered together in parallel bundles called fasciculi.