Answer:
The size up of a motor unit varies from just a few fibers in the precise muscles to over a thousand fibers in the powerful muscles
Explanation:
A motor unit can be defined as a single motor neuron comprising all the muscle fibers that are stimulated by that neuron. Hence, when a motor neuron fires an electrical impulse, all the muscle fibers attached to that unit are contracted simultaneously. This motor unit can be smaller in size such as few neuron fibers to eyes for producing precise eye movement. On the other hand, these neurons can be delivering strong impulses to thousands of neuron fibers such as to leg muscles for producing powerful contractions.
