Yearly is the adverb.
An adverb is a word that modifies verbs, adjectives and other adverbs. In this case "yearly" is modifying "migrate" which is a verb.
I'd say probably when the person you are contacting prefers communicating via call or text or another form of messaging. For almost anything professional or business related, it would be appropriate and acceptable to email.
1. analysis (because when you analyze you study)
2. hobbled
<em>Excuse me but where is the picture for me to answer your question?</em>
<em>Please indicate your picture next time if your gonna ask for something that needs to be seen or observed.</em>
