To develop these four sub-topics:

Consult a general encyclopedia and a specialized encyclopedia for your research (this week’s Learning Materials covers the difference between the two). Do not look for books or articles at this point. Just use encyclopedias. 
You must have at least two encyclopedias for each of your four sub-topics, and only one can be a general encyclopedia. You can use the same general encyclopedia for all four sub-topics.

Write the following as a document for each sub-topic:
Your broad subject area
Your sub-topic
A description of the sub-topic (no more than a paragraph)
Which encyclopedias you used
Create a search vocabulary of that sub-topic.  A search vocabulary is a list of terms and phrases appropriate to your sub-topic that would be useful for searching databases and catalogs.
Pay attention to the terminology used in the encyclopedias to develop your search vocabulary.
You must have at least five but no more than ten terms or phrases for your sub- topic.