What is a distinct characteristic of muscle cells?

Muscle cells are specialized for contraction and movement, which requires a significant amount of energy. To meet this energy demand, muscle cells contain many mitochondria. Mitochondria are the organelles responsible for producing adenosine triphosphate (ATP), the energy currency of the cell, through aerobic respiration. The abundance of mitochondria in muscle cells is crucial because it ensures that these cells can generate the energy needed for their function during physical activity.

The other characteristics listed are not typically associated with muscle cells. For example, while some cells might be flat and thin, muscle cells are generally elongated and cylindrical, allowing them to contract effectively. Additionally, muscle cells need a certain degree of flexibility and are not rigid in structure; instead, they have a unique arrangement that facilitates contraction. Lastly, unlike red blood cells, which lose their nucleus during development, muscle cells do contain multiple nuclei, reflecting their complex structure and function.