18. As long as the little owls remain in the nest, they’re completely dependent on their parents for food. The problem is that the small rodents that they eat can’t be split up. When Mom or Dad returns to the nest to feed their offspring, only one chick can eat a time. In many bird species, the oldest would simply outcompete the youngest, but barn owls are different. __________ Younger owlets groomed older ones more often than older ones groomed the youngsters. And in return, the older owlets fed their younger siblings. In addition, older owlets preferentially offered food to their hungriest siblings, even in the absence of grooming.
(A)It\'s mainly observed when males want to reproduce with females, so there are many exchanges of food.
(B) Food sharing only happened when the researchers artificially provisioned the owlets with extra food.
(C) It is rarely observed and quite impressive that in this species, there are so many cooperative behaviors in chicks.
(D)Remarkably complex examples of cooperation can be found among animal siblings, and even newly hatched barn owls know. that sharing is caring.