Page 25 - Science Tour 3 (Workbook)

Put ( ) or ( ):

1. The atmosphere is a mixture of gases that surround the Earth. ( )

2. Oxygen represents 25% of the atmosphere. ( )

3. Nitrogen represents 78% of the atmosphere. ( )

4. The most abundant gas in the air is carbon dioxide. ( )

5. Oxygen is used in making protein. ( )

6. Plants use carbon dioxide during photosynthesis. ( )

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