(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>
Because it has to be that way
Answer:
chloroplasts
Explanation:
they are the organelles in plant cells that take in sunlight and make energy (photosynthesis)
If your brainstem is destroyed, the left side of your brain could not control the movements of your right hand.
Brainstem- The brainstem is the region at the base of the brain that is located between the cervical spinal cord and the deep cerebral hemispheres. It plays a crucial role in controlling some involuntary bodily functions like breathing and heartbeat.
Spinal cord- A column of nerve fibers that extends from the skull base to the middle of the back. It has three thin membrane-like layers of protecting tissue covering it. The vertebrae encircle the spinal cord and its surrounding membranes (back bones).
To know more about the Brainstem, click on the below link,
brainly.com/question/5351789
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These viral particles, also known as virions, consist of two or three parts: the genetic material made from either DNA or RNA, long molecules that carry genetic information, a protein coat, called the capsid, which surrounds and protects the genetic material. Hope this helped :)