Muscle Contraction In an experiment, the strength of a neural stimulus and the resulting muscle contraction are compared. A single motor neuron that synapses with one muscle fiber is observed in this experiment. One end of the muscle fiber is attached to a mass. The following data was obtained from the experiment. Analyze the data and answer the following questions. A number of Trials Strength of Stimulus (mV) Mass Lifted by Muscle Contraction (g) 1 20 0 2 40 0 3 60 50 4 80 Not Tested 5 100 Not Tested 6 120 50 One student commented that the threshold potential for this muscle fiber is 50 mV. Do you agree or disagree? Why or why not? (2 marks)