[Solved] A friend asks you for a definition of endemic because she is writing a history paper and this word keeps occurring in the literature in reference to bison on the Great Plains of the United States.Your response is that the word endemic means A)a species that has gone extinct since humans have evolved on Earth. B)a species that exists in many habitats on Earth. C)a species that has coevolved with humans on Earth. D)a species that lives in only one area of Earth. Nephron: The structural and functional unit of the kidney. Kidney: A pair of organs in the urinary system that filter waste products from the blood and excrete them in urine. Microscopic Units: Small units of measurement typically used to describe dimensions of cells and microorganisms, not visible to the naked eye. Calyx: The cuplike division of the kidney pelvis.