Element
An element is a pure substance that cannot be broken down into other substances, an element is made up of only one type of atom.
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The answer for this would be the first option. The one that can heavily influence on an ecosystem would be any occurrences that are unnatural. Those occurrences that are unnatural include human activities or any activities that are consciously done to destroy one's ecosystem. Hope this helps.
Answer: Well they simply would have a hard time breathing
Explanation:
Damaging your lungs can prevent your endurance. You would always have shortened breath and you couldn't do much if your lungs are becoming damaged. It will also slow the amount of oxygen you intake which can lead to other problems in your body.