Boreal owls range over a much larger area than do other owls of similar size. The reason for this behavior is that the small mammals on which owls feed are especially scarce in the forests where boreal owls live, and the relative scarcity of prey requires the owls to range more extensively to find sufficient food.
B.Boreal owls range over larger areas in regions where food of the sort eaten by small mammals is sparse than they do in regions where such food is abundant.
有些区域(G),small mammals的食物少(in regions where food of the sort eaten by small mammals is sparse),当然这种区域里的small mammals就少;有些区域(H),small mammals的食物多(in regions where such food is abundant),当然small mammals也会多。B答案就是说:BOREAL 猫头鹰在区域G活动范围比区域H大。这样就和题目的结论一致了。