EQ1. What is a system?
A system is where a set of things work together, sub-consciously or consciously, for something to be accomplished. Organisms adapt to their surroundings for the system to work as everything is self-sustainable in an environment that is biospheric.
EQ2. How humans and the environment are dependent on each other.
The environment provides us with the necessary ingredients, resources and food, we need to survive, the humans capturing these animals and killing them for food to consume. The environment thus requires the humans to protect and conserve for it to thrive and continue to provide us with the resources for us to survive. This can also be called mutualism, but in a bigger way.