A Certain Species of Pine Tree Survives Only in Scattered

A certain species of pine tree survives only in scattered locations at elevations above 2800 metres in the western United States. To understand why this tree grows only in these specific places, an ecologist should

A) investigate the various biotic and abiotic factors that are unique to high altitude.
B) collect data on temperature, wind, and precipitation at several of these locations for a year.
C) conclude that lower elevations are limiting to the survival of this species.
D) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may support their growth.
E) study the anatomy and physiology of this species.