If he studied a small sample it wouldn't be a representative sample. since he got such a large sample there is a chance most likely all organisms follow the rules of evolution.
Answer:
The best answer to the question: The Z disc forms the end____ of a sarcomere, would be: the end border, or the point where sarcomeres join, within a muscle fiber.
Explanation:
Concretely, a Z disc is the boundary line that divides sarcomeres within a muscle fiber. They are the bordes between sarcomeres and they contain the most important molecule, actin, which forms the thin filaments essential for muscle tissue movement. This actin molecule, present along the Z discs, under the correct stimulation and circumstances, will bind to myosin and thus movement will be possible.
So the cells can react to the changes, and so that specialized cells can perform certain functions
