Exploratour: NASA's Exploration for Life
Photosynthesis is the name of the process by which autotrophs (self-feeders) convert
water, carbon dioxide, and solar energy into sugars and oxygen.
If it weren't for the photosynthetic activity of early bacteria, Earth's atmosphere would still
be without oxygen and the appearance of oxygen-dependent animals, including humans,
would never have occurred!
This means one way to detect life's activity on a distant planet is to look for significant levels
of oxygen.
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