Questions with the keyword 'oxygen'

• We breath in oxygen and let out the waste air carbon-dioxide. Why is it that plants breath in the waste air by Resh@science and 1 other. to Chris, Hayley, Jimi Comments: (so far, 2s comments )
• I went on an oceanography trip and we looked at sand. I know that It has a layer of oxygenated sand on the top and the by syra kate to Chris, Hayley, Jimi Comments: (No comments so far )
• why do you need air and oxygen? :o= by domino90 and 1 other. to Chris, Hayley, Jimi, Maddison, Omur Comments: (so far, 11s comments )