F. Clouds and Carbon dioxide. Because CO2 absorbed by trees and clouds gives water to the trees and plants.
Answer: Your brain constantly gets signals from your body which detect the amount of oxygen and carbon dioxide in your blood. Your brain will send signals to the muscles involved in breathing and adjust your breathing rate depending on how active you are.
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Well, i took the test and i put artificial selection and got it right. The definition of artificial selection is "The breeding of plants and animals to produce desirable traits" So the answer is A