Decomposition.

“Our tiniest neighbors, the microbes and bacteria, fungi, and worms who feed on our leftover dinners and yesterday’s news, are the consummate employees. Their bazillions—a single gram of fertile soil may contain fifty million bacteria—are ever on the job, taking no coffee breaks nor personal time off. They ask for no pay, no holiday bonuses, no merit increases. All they require is what is essential for life itself: air and water. What a bargain.”