drag the tiles to the boxes to form correct pairs.

as our current atmosphere formed, the concentrations of various atmospheric gases fluctuated. match each gas with the explanation that best describes how its proportion changed during the evolution of the atmosphere.

hydrogen

ammonia

water vapor

oxygen

carbon dioxide

proportions decreased as it reacted with other elements to form nitrogen.

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proportions increased as this gas was released through volcanic eruptions.

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proportions decreased as this lighter gas was blown away by solar winds.

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proportions increased as plants released this gas into the atmosphere.

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proportions decreased as plants used this gas during photosynthesis.

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