Final answer:
The ratio of white blood cells to body cells is 1 white blood cell to approximately 5,000,000 body cells. So the correct option is D.
Step-by-step explanation:
The ratio of white blood cells to body cells is not easily simplified to a single number because white blood cells can vary widely in number, and there are numerous types of body cells. However, according to the information provided, there are normally only about 1,000 to 11,000 white blood cells per microliter of blood, which suggests that white blood cells are much fewer than the vast number of body cells. Body cells number in the trillions, so the closest answer to the ratio of white blood cells to body cells would be option D) 5,000,000 body cells to one white blood cell.