A homeothermic endotherm has a constant body temperature regulated from within. A heterothermic ectotherm has a fluctuating body temperature regulated by external forces. Answers will vary.
Blood vessels transfer heat to other vessels.
Iguana lizards are ectotherms and are masters at moving about to maintain constant body temperature. Humans are endotherms and they don't usually worry about moving about to maintain body temperature. See page 776 and 777 for a more complete explanation. Drawings should follow Figures 38.16 to 38.19. Several answers may be possible but all should include the reabsorption of water by the system as it follows a concentration gradient.