The capybara is indeed very large for a rodent you correct answer would be either (colonise) in a rainforest environment or (live) in a rainforest environment
Alliteration is the repetition of consonants.
It tells the story in the order it happened. If the story was scattered, the reader would not understand the struggle the character endured for most of the story. for any story recalling an event, sequence is necessary.
I think it is writen correct but i am not sure