1. They depend on the bacteria to keep animals below their status in the food web, so that they can eat, too.
2a. a single tree monkey, I believe.
2b. a group of tree monkeys, a cluster of trees, a pile of rocks, and a fierce wind.
2c. a group of tree monkeys
3. the Sun; the sun provides energy, which is food, to the plants and algae. Then, they are eaten and so on.
4. energy or food
