Observation is broken up into three parts. The first is the date. Then you have the activity and last you have a brief description of what is being observed.
A mathematical model of a food web helps you better understand portions, and track the structure of how the web is flowing. The food web could also help because it helps predict things.
I think the top three statements are the answer.
I am sorry I just wanted points for my answer and I am sorry again I needed points