Does this represent true homeostasis in the fullest sense of the term? Justify your answer.
Yes. This qualifies as homeostasis because body temperature is actively regulated such that internal physiological variables are kept within the range that cells need to function.
No. This does not qualify as homeostasis because homeostasis involves the control of a physiological variable within very narrow limits so that cells can function. The body temperature of a fish fluctuates with the temperature of the external environment.
Yes. This qualifies as homeostasis because a constant body temperature is maintained.
No. This does not qualify as homeostasis because, even though the fish are maintaining relatively constant internal conditions, they are not using a feedback system in order to maintain these conditions.