Final answer:
A 'fixed action pattern' in biology is a hard-wired behavior that, once initiated, proceeds to completion without change, as exemplified by the three-spined stickleback's aggressive response to the color red. The pattern of interest is long-term, stable, and resistant to change once triggered.
Step-by-step explanation:
The student's question revolves around a concept in biology known as a fixed action pattern. This term refers to an instinctual behavior sequence that is hard-wired into an organism's neural circuitry, which will continue to completion once initiated, regardless of changes in the environment. An example of this is observed in the behavior of the three-spined stickleback fish: during the breeding season, male sticklebacks with red bellies display aggressive behaviors towards perceived rivals, which are elicited merely by the stimulus of the color red, even if the object presenting the stimulus does not resemble a fish.
According to the context provided, the correct answer to the student's question about the type of pattern that exhibits little variation over time is d. long-term, stable, and not easily changed. This is because fixed action patterns are consistent, repeatable, and are not subject to significant alteration once they are triggered. These patterns are not short-term or unstable and do not represent a pattern of short-term characteristics nor are they short-term and easily changed.