A. Some boreal owls range over an area eight times larger than the area over which any other owl of similar size ranges. 只比较了boreal owls 和other owls 的活动范围 没有说明活动范围与食物多少的关系 不能起到支持作用
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.
B 是说 Boreal owls rang over 的范围大部分都缺少 small mammals 所吃的食物。
所以,这种食物少-> small mammals 少->单位面积内Boreal owls 能捕到的食物(small mammals)也就少了, 直接支持原文的解释。
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.
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.
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.