What does the idiom stand on her own two feet mean

The significant structural shift that happens between chapters 21 and 22 is

It comes in snatches, dim then keen, the mute, and yet there is no breeze. the best synonym to replace the underlined word would be: a. dumb c. sharp b. soft d. dull

Something there is that doesn't love a wall, that sends the frozen-ground-swell under it, and spills the upper boulders in the sun; and makes gaps even two can pass abreast. the work of hunters is another thing: i have come after them and made repair where they have left not one stone on a stone, but they would have the rabbit out of hiding, to the yelping dogs. the gaps i mean, no one has seen them made or heard them made, but at spring mending-time we find them there. whom does the speaker blame for the gaps in the wall? himself his neighbor nature and hunters rabbits and dogs