In numbers please (no indefinite terms like "most" or "more than half"), and please cite your source.
2007-05-07 12:55:27 · 4 answers · asked by ? 3 in Science & Mathematics ➔ Biology
Approximately 73-87 %
2007-05-07 13:00:02 · answer #1 · answered by Anonymous · 0⤊ 0⤋
I have read estimates from 2/3 to 90%. I personally believe it is closer to 90%. One of the main failures of the so-called "biosphere II" experiment in the Arizona desert was the failure to include enough open water with algae to sustain oxygen production. The O2 levels progressively declined as a consequence, requiring them to be forced to take on outside air and then ultimately end the experiment in failure.
2007-05-07 20:21:34 · answer #2 · answered by Sciencenut 7 · 1⤊ 0⤋
Anything from 50-90%: last I heard (from QI, the British "fact-comedy" show) scientists could not pin it down.
2007-05-07 19:58:30 · answer #3 · answered by rage707_666 2 · 0⤊ 0⤋
do your own homeowork...use google.com. =D
2007-05-07 19:58:33 · answer #4 · answered by Anonymous · 0⤊ 2⤋