The answer is longitudinal study. This is regularly utilized as a part of social-identity and clinical brain research, to ponder fast variances in practices, musings, and feelings from minute to minute or everyday; in formative brain science, to think about formative patterns over the life expectancy; and in human science, to contemplate life occasions all through lifetimes or ages. The purpose behind this is, not at all like cross-sectional examinations, in which distinctive people with similar qualities are looked at, longitudinal investigations track similar individuals, thus the distinctions saw in those individuals are less inclined to be the aftereffect of social contrasts crosswise over ages.
Purpose of given paragraph in the text is to depict the phenomena struggle for existence.
<u>Explanation:</u>
Rapid population growth promotes rapid agricultural and industrial development. And for accommodating such huge population all the natural habitats of wild life is being cleared which accelerates habitat destruction and environmental degradation.
Those who take hunting, gathering as their source of livelihood they suffer lot more due to the deficiency of their food. Gatherers do not get fruits or woods and meats for hunters as well. Because man desperately destroying vegetation and in effect wild life is also destroying. So, to be in world you have to struggle for your existence.
