Answer:
<u>Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.</u>
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Effector muscles
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The answer youre looking for is A
The right option is; b. the water caused an increase in temperature of the air inside the ball and an increase in pressure.
The dent (hollow area formed by pressing or hitting) from the ping-pong ball disappeared because energy was transferred from the hot boiling water in which the ball was placed to the air inside the ball. This transferred energy will increase the temperature of the air inside the ball and the air molecules will begin to move faster with a greater force. Hence, causing an increase in pressure.