Helena slices a sarcomere in half. What can she MOST likely expect to find in the center of it?

The center of a sarcomere is the M line, where thick filaments are anchored. Thick filaments are made of myosin, so Helena would most likely find myosin there. Perimysium and endomysium are connective tissues surrounding muscle structures, and a myofibril is a larger structure made up of repeating sarcomeres.

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