Lichens have been described as "dual organisms<span>" because they are symbiotic associations between two (or sometimes more) entirely different types of microorganism - a fungus (termed the mycobiont) a green alga or a cyanobacterium (termed the photobiont).
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Mice
Because it's eating energy from the plants
<span>Plants take in oxygen all the time for respiration.
Photosynthesis which begins by combining water and CO2, continues in the
"dark phase" in making the glucose molecule. Light is not used for this
part of the reaction so it is called dark , because light is needed for
the first part.
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Plants use Photosynthesis for food and nutrients and produce oxygen in the progress