There would be things everywhere because it didn't decompose ex. orange peels, banana
The earth's tilt. The tilt of the Earth on it's axis is what makes the sun heat up different parts of the Earth at different times, thus making wind, thus making different weather patterns. Depending on how much sun (heat) the area is getting, it changes the weather.
TATCTGG ..... im not really sure sorry.
Ecosystem is a living system, where living organisms interacts with their environment and among each other.
Due to some hazardous processes like, Global warming, Green-house effect, increasing pollution, ecosystem is degrading.
We live in our Ecosystem, if it will get destroyed, our existence would be impossible. So, in order to save ourselves, we need to save it.
That's why biologists, concerned about ecosystem disruption
Hope this helps!