In the text below some words are missing. Drag words from the box below to the appropriate place in the text. To undo an answer choice, drag the word back to the box below the text.
下面的文本缺了一些词。请把词框里的词拖到文中合适的位置；要撤销选择，把词拖回文本下方的词框即可。
Why are moths fatally attracted to the light? is the old glib theory that the moths are trying to use the flame to navigate. does not tell us, , why it is that in many species only males are thus attracted, and in a few, only females. , if moths need to navigate, they must be from a migrating species. most of the time such moths are not migrating. Indeed most species do not migrate at all and thus have no need of navigation.
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