Urban (city) areas rely on food from rural (countryside) areas because in urban citites, there aren't a lot of backyards. People stay in tall apart building built on concrete. There are a lot of streets and sidewalks. Downtown is an urban area. When you go downtown, you don't get much grass and certainly not much open area to grow crops.
Courfeyrac moves to Rue de la Verrerie because he believes that it is more of a center for other people who want to move the Revolution forward. This shows how much he cares about the cause and how ready and willing he is to fight. It also shows, since there is such a large number of people ready to do the same, how badly people want a Revolution. In a politically stable country, there would not be so many people wanting to rise up against the government.
The most probable and most likely answer to this problem would be C. revealed much about their behavior.
Out of the four options presented in this problem, C. would only need a complete subject to make it a correct sentence. Options A. by closely watching and gathering data and B. to terrifying effect would probably need other more words and/or phrases to make them more complete. D. insect studies, on the other hand, can also be considered as a correct option IF insect become the subject.
The sente of sound is D.Watch
