单选题 .  ①The male lion's mane consists of hair of varying length and color, covering, to varying degrees, the head, neck, shoulders, and chest. ②Schaller suggested that the mane protects the area of the body "towards which most social contact is directed" by absorbing blows and bites. ③Darker mane hairs are thicker than lighter hairs, so darker manes may provide better protection. ④These ideas suggest that males with longer and darker manes will be wounded less frequently and/or with less severity on the area covered by the mane, but direct tests of this prediction are difficult. ⑤Individual males are seldom seen daily, and the mane itself obscures many wounds beneath it from view. ⑥Furthermore, even in the best studied population, serious fights between lions are rarely observed.1.  Which of the following best describe the function of the highlighted portion of the passage? ______