Explain why humans cannot impact one of earth's systems without impacting the others.

Earths systems are inervonnected. They interact with each other, moving matter from one system to another, Changes to the atmosphere brought about by human activity eventually lead changes in the biosphere and hydrosphere.

Just as the human body has many systems, which in essence would seem independent, and autonomous, so does the Earth. And the truth is that neither the human body, nor the Earth´s different ecosystems are disconnected, or totally autonomous, from the others. What happens in one place will affect one of the different chains that link them, and it will affect the inhabitants of each of the regions, as well. This is called a domino effect, and it is very real.

So for example, humans may damage the ecosystem of their own cities, with bad waste disposal, water contamination, deforestation and land damage. Even if this happened only in one city, all of these events: deforestation, contamination of water sources, wrong disposal of waste, will of course, affect the individual ecosystem, but through the water, production of contamination gases, extermination of both fauna and flora, and the displacement of different animal species to other areas in order for them to survive, will affect nearby areas, and in the case of gases and water, also further regions as waters go to the ocean, and gases elevate to the atmosphere, causing what we know as global warming.

So it is impossible to say that a human´s actions will not affect the Earth´s systems as a whole.

the underlined phrase is an example of : understatment

would cloning of animals be allowed to prevent extinction?