Which of the following is an example of specialized cells?

Specialized cells are those that have specific structures and functions tailored to perform distinct tasks within an organism. Muscle cells, for instance, are specialized for contraction, enabling the movement of the body and various internal structures. Their unique arrangement of proteins, such as actin and myosin, allows them to generate force efficiently. This specialization is vital for various bodily functions, such as locomotion and maintaining posture.

In contrast, the other options do not represent examples of specialized cells. The assertion that all cells are the same overlooks the vast diversity among cell types, each adapted for particular roles within multicellular organisms. Prokaryotic cells, which include bacteria, are not specialized in the same way as eukaryotic cells. Lastly, while epithelial cells are specialized to form protective barriers and facilitate absorption or secretion, they are only one type among many specialized cells in a multicellular organism. Thus, muscle cells exemplify the concept of specialization most clearly.