Science

2. physical rather than biological; not derived from living organisms.
5. a series of organisms each dependent on the next as a source of food.
7. able to be maintained at a certain rate or level.
9. a system of interlocking and interdependent food chains.
10. a person, company, or country that makes, grows, or supplies goods or commodities for sale.
12. graphical model of energy flow in a community.
13. an organism which lives in or on another organism (its host) and benefits by deriving nutrients at the other's expense.
15. an animal that is hunted and killed by another for food.
16. the surroundings or conditions in which a person, animal, or plant lives or operates.
17. an animal that feeds on other animals.
18. an animal that feeds on plants.
20. a substance that provides nourishment essential for the maintenance of life and for growth.

1. an animal or person that eats a variety of food of both plant and animal origin.
3. a series of events that are regularly repeated in the same order.
4. a person or thing that eats or uses something.
6. the dependence of two or more people or things on each other.
8. he action of conserving something, in particular:
11. the action or process of adapting or being adapted.
13. an animal that naturally preys on others.
14. relating to or resulting from living organisms.
19. power derived from the utilization of physical or chemical resources, especially to provide light and heat or to work machines.