females of all phocid species, by contrast, use a fasting strategy in which mother phocids, having accumulated large energy stores before they arrive at breeding sites, fast throughout the entire lactation period, which lasts from 4 to 50 days depending on the species.
would make it seem that they are mountain dwellers, but
make it seem
E选项:连词since使得It seems that elk would be mountain dwellers和they once ranged over virtually all of the continental United States变成了“因果关系”,但逻辑上“现在Elk像是高山居住者”和“他们曾经在各个地方生存过”是转折关系,应将since改为but。
看清最后部分连词的不同,再去排除
应该是飞行的时候鸣叫比较合适,chattering as it flies