Question

smartart video: motor unit 1 part | -- of 1 point which of the following statements is true concerning motor units? lesser tension is required in lifting a dumbbell than in lifting a cup of coffee. movement of the eyeball requires fewer muscle fibers with less tension being produced. an increased number of motor neurons is needed in precise movements such as lifting a cup of coffee than in lifting a dumbbell. a motor unit consists of all the muscle fibers it controls as well as the area of the spinal cord where it originates. a small number of muscle fibers with increased tension is needed in large, gross movements.

Explanation:

Lifting a dumbbell requires more tension than a cup of coffee, so the first option is false. Precise movements like lifting a cup of coffee require fewer motor - neurons compared to gross movements like lifting a dumbbell. A motor unit consists of a motor neuron and all the muscle fibers it innervates, not the area of the spinal cord where it originates. Large, gross movements require a large number of muscle fibers with increased tension. The movement of the eyeball is a very precise movement and requires fewer muscle fibers with less tension.

Answer:

B. Movement of the eyeball requires fewer muscle fibers with less tension being produced.