EQ1) What is a system?
A system is a structure of events/things that is constant and self-sustainable, such as a food web or a food chain. A system usually has an input, processing, and lastly an output. The components in the system rely on each other to work and live.
EQ2) How humans and the environment are dependent on each other.
Humans and the environment depends on each other very much to live and survive. For example, the seas provide us with seafood like fishes for food consumption and plants photosynthesize to provide humans with oxygen. Without this relationship, the system of the environment would collapse easily. Thus, we should be careful of what we do to the environment, lest we damage it.