| Regulators are also called |
| a) | Endotherms | b) | Exotherms |
| c) | Ectotherms | d) | Either (b) or (c) |
| (a)Regulators are also called endotherms. Evolutionary biological believe that the success of mammals is mainly due to their ability to maintain a constant body temperature (endotherms) and live comfortably whether they are in Antarctica or Sahara Desert |