"He watches from his mountain..." E) These lines use a simile...
A simile is a comparison using like or as. In this example the author is comparing the person falling to a thunderbolt. This comparison shows nature's power.
"As long as I live..." D) These lines give human abilities...
By describing the birds, winds, and waterfalls as singing, the author is giving these non-human things human-like qualities. This is also known as personification.
"I'm only a child..." B) The passage of prose contains a metaphor...
The passage says that "we are all part of a family". This shows how everyone is connected in this metaphor of everyone being in the same family and sharing air, water, and soil.
"I have seen flocks streaming south..." A) These lines contain a hyperbole...
The description of the birds stretching across the entire sky all day long is an over exaggeration of how many birds were actually flying south. While there may have been many, it would not have covered the whole sky, all day long.
"O if we but knew what we do..." C) These lines contain alliteration...
Alliteration is the repetition of the same sound at the beginning of a group of words to create a sound effect. In this passage the "w" sound is repeated to give the passage a rhythm.