Page 26 - Science Tour 3 (Workbook)
P. 26
Give one word:
1. A mixture of gases that surrounds the Earth.
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2. A gas that represents 21% of the atmosphere.
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3. The gas used by plants during photosynthesis.
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4. The gas used by living things to make protein.
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5. The gas inhaled by humans during respiration.
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6. The gas that prevents the Earth from burning.
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