On Monday Mornings, the anxious birds watch rather closely (rather closely is underlined) for the increasingly (increasingly is underlined) rare visits by the rest of the flock.

Question

Which underlined adverb describes another adverb?

Answer 1

If you understand adverbs, you'll see which one of those three adverbs describes another adverb.

http://www.englishclub.com/grammar/adverb-what.htm

Answer 2

Like Ms.Sue said you need to understand adverbs.