Final answer:
A single stimulus stretch in a muscle can elicit two different motor responses: a twitch and a graded muscle response.
Step-by-step explanation:
When a single stimulus stretch is applied to a muscle, it can elicit two different motor responses: a twitch and a graded muscle response.
A muscle twitch is a single contraction that consists of a latent period, a contraction phase, and a relaxation phase. On the other hand, a graded muscle response refers to the variation in muscle tension produced by changes in the frequency of action potentials and the number of motor neurons transmitting those action potentials.