Given a scientific passage and an answer, generate a question for the given answer.

Passage: Figure 33.18 Smooth muscle cells do not have striations, while skeletal muscle cells do. Cardiac muscle cells have striations, but, unlike the multinucleate skeletal cells, they have only one nucleus. Cardiac muscle tissue also has intercalated discs, specialized regions running along the plasma membrane that join adjacent cardiac muscle cells and assist in passing an electrical impulse from cell to cell. Answer: striations
Skeletal muscle cells and cardiac muscle cells share what property, which is not shared by smooth muscle cells?