the foundation of our living on this planet is oxygen, it comes first/ as we die quickly without it. oxygen is a periodic element: which means it is a distinct atom/ wrapped by the neutron is a specific way. OR MORE SIMPLY; WE DO NOT/ (trees, oceans, etc) MAKE OXYGEN, it is a finite resource; gone is gone. the biosphere 2 experiment enclosed 7 million cubic feet of atmosphere; intended for living 2 years inside by 8 people to prove “we can travel the universe”. they broke out after two months; because the oxygen went from 21% saturation of air/ to 14% saturation of air (like living on top of mount Everest. a lesson in university: while they had “endless plans” to deal with every scenario/ not a single one about running out of oxygen.