How are muscle cells characterized in terms of shape?

Muscle cells are characterized by their elongated and thin structure, which allows them to contract efficiently. This shape is essential for their function, as long and thin muscle fibers can shorten significantly during contraction, generating the force necessary for movement. This morphology is particularly evident in skeletal muscle cells, which are striated and multinucleated, as well as in smooth muscle cells, which are elongated but lack striations. In cardiac muscle, while the cells may branch, they still retain a longer shape compared to other types of cells. The other options do not accurately represent the typical structure of muscle cells, as they are not square, blob-like, or root-like, each of which would not support the functional needs of muscle contraction.