I felt somehow betrayed when I learned that the oxygen trees release comes off the water that's used for photosynthesis, and not the carbon dioxide directly. (

I felt somehow betrayed when I learned that the oxygen trees release comes off the water that's used for photosynthesis, and not the carbon dioxide directly. (Of course, the oxygen in the carbon dioxide ends up in new water molecules in a later step of photosynthesis, and that water either immediately or eventually finds itself in another photosynthesis reaction, so that carbon dioxide oxygen finds itself released into air sooner or later, but still.)