Question 13 1 pts 13. each year there are close to billion trees planted in the united states o six o five o two o one question 14 1 pts 14. the reason certain types of trees dominate a region is because of a natural process called wildlife o succession o overstory o deciduous question 15 1 pts 15. an area where all living and nonliving features depend on each other is called an o preservation o industry o axygen system o ecosystem