Questions with the keyword 'oxygen'

• why won’t the carbon dioxide levels decrease if there are more people in the earth and starting to be less plants that by embmay to Amy, Drew, Julia, Kimberley, Sara Comments: (so far, 2s comments )
• when we are born how do we know how to breathe by botter7r2 to Amy, Drew, Julia, Kimberley, Sara Comments: (so far, 4s comments )
• how do trees give us oxygen by botter7r2 to Drew Comments: (No comments so far )