Respuesta :
The ecologoists are studying the Population of the species ( D )
Population of species
The population of species is a group of organisms/individuals of the same specie that live together in a defined geographic area also interbreeding with eachother. The study of how the number of individuals for a particular specie changes overtime is a study of the population of the species.
Hence we can conclude that The ecologoists are studying the Population of the species ( D ).
Learn more about Population of species : https://brainly.com/question/13403673