The very elusive falcon flies too quickly to be easily captured. which underlined adverb modifies an adverb?

Umm, there's nothing underlined or bolded or anything, but the adverb "too" modifies the adverb "quickly," so I would go with "too."

The only word I know that could be modified is "too."

is basically a good source of getting and others by what you know for example if someone asked a question and you know the answer you could answer it and get some points or if you need on a question you could make a post about it and wait till someone answers it or just look up the question and see if someone else has asked about it