The structural level in which the muscle produces the contraction is known as the muscle fiber.
<h3>What is a muscle fiber?</h3>
A muscle fiber is a single muscular cell that is able to contract by using specialized proteins such as filaments of myosin and actin.
This unit (muscle fiber) is able to contract both in vivo and in vitro by establishing suitable environmental conditions (e.g., proper calcium levels).
In conclusion, the structural level in which the muscle contracts is the muscle fiber.
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Answer:
A to protect them from the sun but still allow air to flow near their skin.
Explanation:
I think
The sodium could move through the cell's membrane by diffusion.
Diffusion<span> is the net movement of molecules or atoms from a region of high concentration (or high chemical potential) to a region of low concentration (or low chemical potential) as a result of random motion of the molecules or atoms.</span>
I believe it’s the first one
