What is the contour interval for this map? please help !!!

Regarding most of the narrator’s story, which word best describes the tone?

Which of the following describes a boom period? a. as one population increases, another population decreases. b. as one population increases, the other population also increases. c. as one population decreases, another population increases. d. as one population decreases, another population also decreases

Which does not describe a physical change happening to water? water evaporating in the sun water reacting with nitrogen gas water freezing and being broken apart with a knife water heating up on a stove