B, within a certain range, when fever, human immune function is obviously enhanced, which is conducive to eliminating pathogens and promoting disease recovery. Therefore, antibiotics are not necessary when the body temperature is not too high; However, if the body temperature exceeds 40℃ (over 39℃ in children), it may cause convulsion, coma and even serious sequelae, so antipyretics should be used in time. Therefore, fever has both advantages and disadvantages to the human body.
C, in the process of breathing, energy is released, some in the form of heat energy, and most of the energy is used for the needs of biological life activities.
D, the activity of digestive enzymes is affected by temperature, and both high temperature and low temperature will inhibit the activity of enzymes; The enzyme has the highest activity in human body, and its catalytic effect is the strongest at about 37℃.
So choose: D.