Each of the prompts for this assignment asks you to compare two topics: paper and plastic, vegetarian and omnivorous diets, etc.
When thinking about sources, however, avoid limiting your search to articles that directly compare the two topics. You might choose to start by searching for articles that compare the two topics--and you might find some!--but in many cases, you will explore the subject in greater depth if you locate some sources about each topic and make the comparisons yourself.
For instance, suppose your topic is comparing electric and conventional vehicles. You might look for articles that talk about both by using a search like this, in a library database:
electric vehicles AND traditional vehicles AND environmental impact
Or in Google, you might put
electric vehicles vs. traditional vehicles environmental impact site:.gov
However, to make sure you're getting a good look at what's available, you should also search for each topic separately. In the databases, do separate searches for
electric vehicles AND environmental impact
And
traditional vehicles AND environmental impact
And in Google, try
electric vehicles environmental impact site:.gov
Followed by,
conventional vehicles environmental impact site:.gov