D is the best answer. Hope this helped :)
<span>All the muscle fibers under the control of a single motor axon are referred to as </span>Motor Unit. <span>A </span>motor<span> unit is made up of a </span>motor<span> neuron and the skeletal </span>muscle fibers <span>stimulated by that </span>motor<span> neuron's </span>axonal<span> terminals. Groups of </span>motor<span> units often work together to organize the contractions of a </span>single<span> muscle.</span>
Oxygen and it removes all other toxin