science

3. organisms that break down waste and the remains of other organisms to return the raw materials back to the ecosystem
8. Pyramid models that show how energy flows through ecosystems
10. the variety of life in the world or in a particular ecosystem or habitat
11. an association between two organisms in which one benefits and the other derives neither benefit nor harm.
13. factor The tendency for the death rate in a population to increase, or the birth or growth rate to decrease, as the density of the population increases
14. Factor A non-living feature of an ecosystem (rock, water, sun, etc.)
15. an organism that obtains energy from feeding on another organism

1. an interaction between organisms or species for resources - food, shelter, etc.
2. a relationship between two species of organisms that both benefit from the relationship
4. factor The tendency for the death, birth or growth rate in a population neither to rise nor fall as the density increases
5. Chain the order in which matter and energy in the form of food is transferred from one organism to another
6. Web a network of food chains or feeding relationships
7. Cycle the transfer of carbon through naturally occurring processes between organisms and the environment
9. the living together of two organisms or species in the same habitat without trying to eliminate the other
12. Factor A living feature of an ecosystem (plants, animals, leaves, etc.)