White Shark
Experiments have been made with closed systems and people and animals living inside closed system.
There was a small "Jungle" of plants and trees inside.
It was a huge area covered with glass, 100% isolated from the outside world.
Oxygen levels, CO2 and
CO levels were monitored.
Animals and humans and plants produce CO2 and CO.
Only plants produce Oxygen.
In the end, CO2 levels were too high, oxygen too low, and they had to add more oxygen.
Apparently. each animal and each human need one small jungle.
One small jungle for several humans and several animals was not enough.
WS