Answer:
cells are the innermost source of energy in all organisms. please give me brailiest
(1) The varying number of muscle fibers that contract
<span>In most muscles, the number of muscle fibers in different motor units ranges from a few to hundreds. The nervous system can thus regulate the strength of contraction in a muscle by determining how many motor units are activated at a given instant and by selecting large or small motor unties to activate. </span>
some muscles are almost always partially contracted. In such muscles, the nervous system my alternate activation among the motor units, reducing the length of time any one set of fibers is contracted. Prolonged contraction can result in muscle fatigue due to the depletion of ATP and dissipation of ion gradients required for normal electrical signals.ing.
<span>(2) varying the rate at which muscle fibers are stimulated </span>
<span>single action potential produces a twitch lasting about 100 msec or less. If a second action potential arrives before the muscle fiber has completely relaxed, the two twitches add together, resulting in greater tension. Further summation occurs as the rate of stimulation increases. When the rate is so high that the muscle fiber cannot relax at all between stimuli, the twitches fuse into one smooth, sustained contraction called tetanus.</span>
The correct answer is <span>d. 62%.
Since Ellie's decision will be based 100 % on Janice's decision, the probability that both will attend the class is 62 % because that is the chance that Janice will attend the class. Since Ellie just depends on Janice, the correct answer is </span><span>d. 62%. I hope this answer helped you. </span>
To prevent blood flowing back after each heartbeat. They ensure that the blood flows only in one direction (back to the heart).
A giraffe often has to to be aware of its surroundings since they could get ambushed by a predator thats why they mostly stay in pairs or groups
