Now, on Earth, the green plants have, by the process of photosynthesis, found a way of converting the relatively high-frequency photons coming from the Sun to photons of a lower frequency, using this gain in low entropy to build up their substance by extracting carbon from CO2 in the air and returning it as O2. When animals eat plants (or eat other animals that eat plants), they use this source of low entropy, and the O2, to keep down their own entropy.
