The system of classification relates to the diversity of species because the system of classification is how we organize the diversity of species. With out it we would have a hard time trying to determine which animals belong with which group. There would be no order, just chaos of trying to determine animal likeness of one another.
To cut this answer short, it helps them organize organisms.
Green plants are autotrophic and synthesize or make their own food by the process of photosynthesis. They do this with the help of carbon dioxide and water in the presence of sunlight. ... Their corresponding modes of nutrition are known as the autotrophic and heterotrophic mode of nutrition.
Although the DNA packaging with histones proteins is mean to form nucleosomes (groups of 8 histones proteins), the higher structures why the genetic material is packaged with those molecules is to form chromosomes, as you said.
Both have a way to get rid of waste materials