Plants are engines powered by the Sun. The very purpose of those leaves is to tap the flow of solar energy. When the giant celestial nuclear reactor is taken into account, the entropy of the entire system is increasing.
Plants are engines powered by the Sun, made almost entirely out of water and air.
Just had to throw that in, otherwise I would have modded up your answer.
The comparison to Wal-Mart is particularly apt.
A better comparison is the Sears catalog, for those who remember it.
If you're not careful, you're going to catch something.