The materials cycled through ecosystems during the nitrogen cycle and the carbon cycle a. remain at constant levels, although the form and location of the materials can change. b. decrease steadily until more of the materials are added from outside systems. c. increase or decrease based on the number of producers in the ecosystem. d. remain at constant levels and cannot change form or location within the ecosystem.

11. gene12. allele13. crossing over14. linked15. gene16. x17. males, femalesapologies if numbers are out of order.

The return of the wolf to yellowstone national park will probably affect the bird population to some degree, not significantly. while wolves will hunt birds when necessary, they prefer to hunt larger prey. the bird population will most likely only be affected when hunting is scarce for the wolves. birds of prey will also probably not be affected as much as other birds who spend more time on the ground hunting for food as the tend to spend more time in the air or in trees since they do not need to stay on the ground for long due to the nature of the way they hunt.