The correct answer is option a. responding to the environment.
The sweating is the release of sweat from the sweat glands. The sweating releases the water molecules on the skin surface as a result of increased body temperature due to changes in atmospheric temperature. The water molecule from the skin evaporates causing a decrease in body temperature.
The panting increase in the heat loss by respiration, hence, it is also a respond to the increased atmospheric temperature. So, both the conditions are associated with the temperature increase outside the body, here change in temperature act as stimuli and body react according to change.