<span>Countercurrent oxygen exchange I think
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The answer is Light exposure
They release CO2 (just like us, when we breathe). But, when plants are photosynthesizing. They release the oxygen through the same pores that allow the CO2 to enter their leaf cells.
The answer is B. The planets were all formed from dust that was orbiting around the sun.
I believe it is A (Adenine)
