Well, it’s much like your body. Intellectually, you can think of your toe as being something other than, say, your nose. They have different functions and look different. But at the same time you understand that all of those different pieces are interconnected and work together in a way that isn’t quite captured by thinking of them in terms of a collection of parts. It’s all a unitary “you”.

If you allow that “you” to keep going beyond the limits of your skin, so that the world itself stops looking like a collection of parts, it’s possible to see this all as a unitary “you” that includes all of us and that which sustains us.

This sounds like homework. (?)
Everything is interdependent. There are some good books written about how population and cities grew where they did. I can’t remember the author. Easter Island is a good collapse story. (Rapa Nui)

”...merely the ecosystem” is a bit of understatement. The ecosystem (which IS “the environment”) includes the planet’s inhabitants. And, given the Law of conservation of matter, one may argue the whole Universe is a single ecosystem with everything interrelated.

What is the relationship of planet’s inhabitants to the planet’s natural resources (which is merely the ecosystem), to themselves, to each other, and to the environment?

The planet’s inhabitants are the living things (plants, insects, fish, fungi, bacteria, viruses, animals, etc) on the planet. They live in the planet’s environment, which has many diverse parts with different properties. They are also part of that environment, because the environment refers to everything there. Calling some of those things “resources” means that some things are beneficial to living things. Different things are resources to different types of inhabitants, and some inhabitants are resources to others. The way in which inhabitants use other things in the environment varies quite a lot, including food, shelter, useful objects, materials for building, water, shade, nice views, open spaces, clean air, sunlight, heat, etc. Each species and even tribes or individuals within species have different types of relationships to themselves and to other inhabitants of the same or different species. Sometimes they take advantage of each other, eat each other or fight; other times they help each other, work together, or get along, based on their needs and past experiences. The inhabitants as a whole are able to remain living because of the great variety of different inhabitants and the differences between them, which create a complex balance between all of them, so that when something disrupts the situation, other things react and balance that out. For example, as one species’ population grows particularly large, its own activities tend to use up more and more of the resources it needs, and it presents an opportunity to other species who can use it and its activities and byproducts as resources, either or both of which will eventually lead to the overpopulated species’ population decreasing, especially if/when it eradicates most/all of the resources it needs.

The planet’s surface (inhabiting species) is the ecosystem. This includes everything from the largest organisms (some consider the Great Barrier Reef to be a macroorganism), to the microbes that reside on or within other microbes.

self-edited

Everything on earth; each part, whether animal, mineral and vegetable, make up the environment. It can also be thought of as the ecosystem but more correctly the ecosystem is how these individual parts found in the environment are connected, how they function or interact amongst themselves. Natural resources is commonly used to refer to the items as they are used to benefit Man. If you expand the definition to encompass all life forms you can say that a natural resource is something found in the environment that can be utilized in a beneficial way by some other thing.
Each thing is a natural resource for something else and how they all combine in a working fashion is the ecosystem which all takes place in the environment.

Man has been very successful at adapting to live harmoniously within the many varied ecosystems on our planet from the desert, tropical jungle and even the arctic. Whole ancient civilizations were also wiped out when they overwhelmed and upset the balance of the ecosystem they attempted to live in. Modern man has created new technologies that enable man to live almost artificially in areas that could not sustain or support man’s survival.

For a neat look into man-made eco-systems check out Biosphere 2

Can we sue the ants & termites? The culpability of the rats & mosquitos must be in the billions.