Answer:
Online class is being taken by us.
Looking up words in a dictionary will improve reading COMPREHENSION and vocabulary.
I'm taking it that this is a question that is related to library science? If so, then the information that it should document should be the author of the book that is presented, the title of the work, and who published such work. This is to make convenient tracking or retrieval of the document wished to obtain.
Out of the choices given, the concrete nouns are toolbox, lamb, iron, and tooth.
