Answer:
Root words are parts of words which cannot be divided any further, but which have some kind of meaning on their own. Here, I believe that root words are cred, graph, and vis.
Cred (as found in credible, credibility), means something believable; graph (as in graphic) means to write; vis (as in visible) means to see. Anti, con, and post are all prefixes, which means they are added to words and cannot be root words thus.
This is a sentence. You can tell because it has a subject (Imala) and a verb clause (will play). In addition, it has a direct object *what she is playing* (the solo) and a prepositional phrase for some added clarity (in the concert).
