Tetanus is a(n):
a. muscle contraction of sustained force resulting from repeated action potentials.
b. contraction where the muscle does not change length.
c. contraction caused by a single action potential.
d. contraction that slowly increases in force.
e. abnormal muscle contraction.

a. muscle contraction of sustained force resulting from repeated action potentials.

Explanation:

Tetanus is a symptom consisting of the constant contraction of one or more muscles. This can be caused by diseases or other physiological conditions that cause an increase in the frequency of action potentials that promote muscle contractions. Thus, the contractions overlap each other and consequently the muscle remains in a condition of constant contraction.

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms