TOP 阅读11 第三篇的问题, 请大家帮忙解答

juliagoUID: 2912431

The younger of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relative
红色部分是用的倒装， 为什么这样写？
Therefore, a begging nestling that secures food at the expense of its siblings might actually leave behind fewer copies of its genes overall than it might otherwise.
后面怎么翻译啊？

还有第四题为什么不选A呢？

juliagoUID: 2912431

那位牛人能回答一下么?

juliagoUID: 2912431

自己顶一下

crysmileUID: 2528832

The young of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relatives.
在地面上筑巢的莺的幼鸟发出比它们的在树上筑巢的亲戚更高频率的叽叽声。

Therefore, a begging nestling that secures food at the expense of its siblings might actually leave behind fewer copies of its genes overall than it might otherwise.
因此，如果一只奋力啼叫的雏鸟以牺牲兄弟姐妹为代价来确保自己能得到食物，那么，总的来说，这种鸟儿实际上可能会比它不这么做留下更少的基因。
（意思就是说，如果雏鸟没有故意大声啼叫伪装很饿来独占食物，它的兄弟姐妹也能活下来，这样对鸟类总体本身更好。）
（牺牲兄弟姐妹指的是这种行为：不饿也大声啼叫，和其他幼鸟争抢食物）

结合上下文理解一下。