"what is the relationship between the motor neuron axons and muscle fibers"

Motor neurons carry impulses to the effectors in the body, which are the muscles or glands that produce a change based on a stimulus sensed by the receptors. The motor neurons "innervate" muscle fibers, which essentially means that they cause them to move. The fewer the muscle fibers associated with a motor neuron, the more precise are the movements of those fibers. Having to control a small number of fibers, the neuron is able to coordinate more dexterous motions. An example of a region where there are not a lot of muscle fibers related to each neuron is in your fingers.

Then it is june the conclusion to the second sentence is just restating "if it is june then it is summer"