title: Red blood cell
context: Adult humans have roughly 20–30 trillion red blood cells at any given time, constituting approximately 70% of all cells by number.[18] Women have about 4–5 million red blood cells per microliter (cubic millimeter) of blood and men about 5–6 million; people living at high altitudes with low oxygen tension will have more. Red blood cells are thus much more common than the other blood particles: there are about 4,000–11,000 white blood cells and about 150,000–400,000 platelets per microliter.
question: How many red blood cells are in the human body?
answers: 20–30 trillion