Answer:
plants
Explanation:
plants need carbon dioxide to survive, so if they cant take Co2 they cant make oxygen meaning no human life.
To summarize this, they were afraid. During that time, we had just managed to successfully leave the British government, and the whole reason we declared independence was because of an all-powerful king who controlled our lives through massive taxation, without listening to anything we said. We had developed a fear of a strong, central government like the British, so we did as much as we could to weaken our new government, even abolishing federal taxes, which meant no federal military or funding for anything like education, health, or safety at the federal level.<span />
Its because of people burning fossil fuels and causing pollution.
Hope This Helps You!
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I don't know who De Vaca is but by context clues I would infer that he realized that Native Americans where not the savages they where thought to be.