4. (1)self-serving bonds exist between unrelated members of the animal kingdom. (2)take the leopard and the battler eagle, for instance. (3)a leopard will go to any lengths to keep other animals from its kill, even to the point of storing the carcass high above the ground in the fork of a tree. (4)but the leopard enters into a firm partnership with the battler eagle who, in return for a share of the meat, guards the kill and warns the leopard about potential poachers. (5)or consider the rhinoceros and its flocks of tickbirds and egrets. (6)the rhino, nearly blind, relies on the birds’ eyesight to warn it of approaching danger, while the birds fill themselves up on the host of ticks and other parasites infecting the rhino’s hide. (7)even in the ocean, these beneficial relationships flourish. (8)moray eels and cleaner fish, for example, peacefully inhabit the same reef. (9)the cleaner fish get an all-you-can-eat dinner on the eel’s parasites, and the eel receives a free grooming session. the sentence that expresses the main idea is: (choose the number of the sentence. then click “go.”)