Why did local phone companies have a natural monopoly before the arrival of cellular technology?

What happen to eastern europe after ww2

Most of the volcanic activity that occurs in the ring of fire is a result of the a. formation of mantle plumes away from plate boundaries. b. subduction of one plate under another. c. movement of two plates away from each other. d. sliding of one plate past another.

19. which type of volcano is shown in the image? a. shield volcano b. fissure c. ash-cinder volcano d. composite volcano