Question

which statement best explains why sensors (or senses) are necessary to produce a change in behav
a. stimuli must be sensed in order to produce a response.
b. organisms cannot sense stimuli without a central nervous system.
c. stimuli must be responded to in order to be sensed.

Explanation:

The question asks why sensors/senses are necessary for behavioral change. Option A correctly links sensing stimuli to producing a response—without detecting a stimulus (via senses), an organism cannot initiate a behavioral change. Option B is wrong because some organisms (e.g., bacteria) sense stimuli without a central nervous system. Option C reverses the logic: sensing comes before responding, not the other way around.

Answer:

A. Stimuli must be sensed in order to produce a response.