A certain species of pine tree survives only in scattered locations at elevations above 2800 meters in the western United States. To understand why this tree grows only in these specific places, an ecologist should _____.
A) conclude that lower elevations are limiting to the survival of this species
B) study the anatomy and physiology of this species
C) investigate the various biotic and abiotic factors that are unique to high altitude
D) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may support their growth
E) collect data on temperature, wind, and precipitation at several of these locations for a year

The survival of the certain species of pine trees only at elevations shows that there will definitely be a biotic or abiotic factor that enhances the growth of the pines at that place. It might be due to abiotic factors like the temperature or soil at high altitude or due to some biotic factor like a mutualistic relationship with organisms at high altitudes. Hence, option C is the correct option.