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The distance between 1 and 7 spans a sarcomere correspond the structure at B is covered by the perimysium.
<h3>What is the smallest contractile unit within skeletal muscle?</h3>
A sarcomere comprises the segment between two consecutive Z lines and is the contractile unit of the muscle fiber, as it is the smallest portion of the muscle fiber capable of contraction and distension.
In this case, the distance between points 1 and 7 has the smallest structure of a skeletal muscle and corresponds to figure B.
See more about sarcomere at brainly.com/question/14005497
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This is referred to as Sleep Apnea.