She just said plants produce oxygen, no stars produce oxygen!!! How hard is this to get right?!,(reply>), @Hexanitrobenzene Oxygen is bound to get bound, because of its corosive nature.<br><br>Indeed O2 is the only oxygen insects and animal can breathe.<br><br>Now the climatenutcases want to extract CO2 from the atmosphere. Which is literally the way to kill every living thing on this planet.<br><br>Plants grow slower and less healthy with a low amount of CO2. Which in turn causes the levels of O2 to drop. Because the only way those plants are going to excrete O2 is by fotosynthesis. That removes the carbon from the CO2.,(reply>), @Saint Kaaz <br>We are using different definitions of "oxygen". You are calling "oxygen" every atom with 8 protons in any molecule. Using this definition, you are right. However, for the purpose of search for life, it's too broad - what's the use of the bound oxygen atoms if they can't be used for breathing ? In this case, only molecular oxygen, O_2, is interesting.,(reply>), @Hexanitrobenzene Nonsense!<br><br>Oxygen survives. Burn something and the oxygen fuses with other moleculen like carbon. Then you get CO2. Nothing is gone, its all there.<br><br>The plant uses the CO2 and lets the O2 out again. So the oxygen was never gone, just like the carbon!,(reply>), Wrong context. Yes, oxygen atoms are "born" in stars. However, we are talking about an environment of a planet. There it quickly reacts with hydrogen, carbon, silicon, etc. If there is no source of continual replenishment, molecular oxygen does not survive in an atmosphere. That's why it is thought to be a good "hint" of life, at least of the kind similar to one on our Earth.